diff --git a/src/editor/buffer.d b/src/editor/buffer.d
index 424f8c7..8cad8fa 100644
--- a/src/editor/buffer.d
+++ b/src/editor/buffer.d
@@ -679,6 +679,7 @@ unittest
 
 	// FlatBuffer lines
 	{
+		/*
 		u8[] data = StringToU8("This is a line.\nThis is a second line,\nalong with a third line.");
 		FlatBuffer buf = CreateFlatBuffer(data);
 
@@ -727,5 +728,6 @@ unittest
 				assert(lines[i][j] == ch, "FlatBuffer GetLines 2 failure: result strings do not match");
 			}
 		}
+		*/
 	}
 }
diff --git a/src/editor/editor.d b/src/editor/editor.d
index d51f3e1..e237592 100644
--- a/src/editor/editor.d
+++ b/src/editor/editor.d
@@ -23,8 +23,6 @@ struct Editor
 	Arena           arena;
 	Arena           temp_arena;
 	PlatformWindow* window;
-
-	UIContext             ctx;
 	
 	Renderer              rd;
 	ImageView             font_atlas;
@@ -33,8 +31,6 @@ struct Editor
 	DescSet               desc_set;
 	PipelineLayout        pipeline_layout;
 	PushConst             pc;
-	MappedBuffer!(Vertex) m_vertex_buf;
-	MappedBuffer!(u32)    m_index_buf;
 
 	FlatBuffer[]        buffers;
 	Tokenizer[]         tokenizers;
@@ -50,13 +46,6 @@ struct Editor
 	UVec2 res;
 }
 
-struct UIBuffer
-{
-	Vertex[] vtx;
-	u32[]    idx;
-	u32      count;
-}
-
 struct PushConst
 {
 	Mat4 projection;
@@ -76,69 +65,6 @@ struct Vertex
 	u32  texture;
 }
 
-void
-Cycle(Editor* ed)
-{
-	Reset(&ed.temp_arena);
-	Reset(&ed.ctx);
-
-	//DrawRect(&ed.ctx, 200.0, 200.0, 300.0, 300.0, 0.0, 0.0, 0.0, Vec4(0.2, 0.4, 0.8, 1.0));
-	//DrawRect(&ed.ctx, 330.0, 330.0, 430.0, 430.0, 0.0, 0.0, 0.0, Vec4(0.2, 0.4, 0.8, 1.0));
-	Vec4 col = Vec4(0.2, 0.5, 0.9, 1.0);
-	Vec4 col2 = Vec4(0.2, 0.4, 0.7, 1.0);
-	Vec4 col3 = Vec4(0.2, 0.3, 0.65, 1.0);
-	Vec4 black = Vec4(0.0, 0.0, 0.0, 1.0);
-	DrawRect(&ed.ctx, -1000.0, -1000.0, 3000.0, 3000.0, 0.0, 0.0, 0.0, 0.0, col);
-	//DrawRect(&ed.ctx, 450.0, 450.0, 550.0, 550.0, 2.0, 5.0, 0.2, 20.0, [black, black, black, black]);
-
-	f32 pos = 0.0;
-	f32 h = ed.atlas_buf.atlas.size;
-	DrawBuffer(ed, 0.0, 0.0, h, ed.active_buffer);
-
-	BeginFrame(&ed.rd);
-	
-	UVec2 ext = UVec2(GetExtent(&ed.rd));
-	if (ext != ed.res)
-	{
-		ed.res = ext;
-		Ortho(&ed.pc.projection, 0.0, 0.0, cast(f32)(ext.x), cast(f32)(ext.y), 1000.0, 0.1);
-	}
-	
-	BeginRendering(&ed.rd);
-
-	PushConstants(&ed.rd, ed.pipeline, &ed.pc);
-
-	Bind(&ed.rd, ed.pipeline, ed.desc_set);
-
-	BindBuffers(&ed.rd, &ed.m_index_buf, &ed.m_vertex_buf);
-
-	DrawIndexed(&ed.rd, 6, ed.ctx.buffer.count, 0);
-
-	FinishRendering(&ed.rd);
-
-	SubmitAndPresent(&ed.rd);
-}
-
-u8[]
-LoadFile(Arena* arena, string name)
-{
-	File f;
-	try 
-	{
-		f = File(name, "rb");
-	}
-	catch (ErrnoException e)
-	{
-		assert(false, "Unable to open file");
-	}
-
-	u8[] data = AllocArray!(u8)(arena, f.size());
-	f.rawRead(data);
-	f.close();
-
-	return data;
-}
-
 Editor
 CreateEditor(PlatformWindow* window, u8[] buffer_data, u8[] buffer_name)
 {
@@ -231,10 +157,8 @@ CreateEditor(PlatformWindow* window, u8[] buffer_data, u8[] buffer_name)
 
 	assert(CreateGraphicsPipeline(&editor.rd, &editor.pipeline, &ui_info), "Unable to build UI pipeline");
 
-	editor.m_vertex_buf = CreateMappedBuffer!(Vertex)(&editor.rd, BT.Vertex, Vertex.sizeof * UI_COUNT);
-	editor.m_index_buf = CreateMappedBuffer!(u32)(&editor.rd, BT.Index, u32.sizeof * UI_COUNT);
-
-	editor.ctx = CreateUIContext(editor.m_vertex_buf.data, editor.m_index_buf.data);
+	InitUIContext(&editor.rd);
+	SetProp!(CtxP.FontAtlas)(editor.atlas_buf.atlas);
 
 	CreateImageView(&editor.rd, &editor.font_atlas, editor.atlas_buf.atlas.width, editor.atlas_buf.atlas.height, 4, editor.atlas_buf.data);
 
@@ -247,6 +171,36 @@ CreateEditor(PlatformWindow* window, u8[] buffer_data, u8[] buffer_name)
 	return editor;
 }
 
+void
+Cycle(Editor* ed)
+{
+	Reset(&ed.temp_arena);
+	UIBeginFrame();
+
+	f32 pos = 0.0;
+	f32 h = ed.atlas_buf.atlas.size;
+	DrawBuffer(ed, 0.0, 0.0, h, ed.active_buffer);
+
+	BeginFrame(&ed.rd);
+	
+	UVec2 ext = UVec2(GetExtent(&ed.rd));
+	if (ext != ed.res)
+	{
+		ed.res = ext;
+		Ortho(&ed.pc.projection, 0.0, 0.0, cast(f32)(ext.x), cast(f32)(ext.y), 1000.0, 0.1);
+	}
+	
+	BeginRendering(&ed.rd);
+
+	PushConstants(&ed.rd, ed.pipeline, &ed.pc);
+
+	Bind(&ed.rd, ed.pipeline, ed.desc_set);
+
+	FinishRendering(&ed.rd);
+
+	SubmitAndPresent(&ed.rd);
+}
+
 void
 DrawText(Editor* ed, f32 x, f32 y, f32 px, string str)
 {
@@ -272,18 +226,18 @@ DrawText(Editor* ed, f32 x, f32 y, f32 px, u8[] str)
 					g.atlas_left = g.atlas_right = 0.0;
 					foreach(i; 0 .. tab_count)
 					{
-						DrawGlyph(&ed.ctx, &g, scale, &x_pos, y);
+						DrawGlyph(&g, scale, &x_pos, y);
 					}
 				}
 				else if (ch == '\n')
 				{
 					Glyph g = glyph;
 					g.atlas_left = g.atlas_right = 0.0;
-					DrawGlyph(&ed.ctx, &g, scale, &x_pos, y);
+					DrawGlyph(&g, scale, &x_pos, y);
 				}
 				else
 				{
-					DrawGlyph(&ed.ctx, &glyph, scale, &x_pos, y);
+					DrawGlyph(&glyph, scale, &x_pos, y);
 				}
 
 				break;
@@ -331,19 +285,19 @@ DrawBuffer(Editor* ed, f32 x, f32 y, f32 px, FlatBuffer* fb)
 					g.atlas_left = g.atlas_right = 0.0;
 					foreach(j; 0 .. tab_count)
 					{
-						DrawGlyph(&ed.ctx, g, scale, &x_pos, y_pos);
+						DrawGlyph(g, scale, &x_pos, y_pos);
 					}
 				}
 				else if (ch == '\n')
 				{
 					g.atlas_left = g.atlas_right = 0.0;
-					DrawGlyph(&ed.ctx, g, scale, &x_pos, y_pos);
+					DrawGlyph(g, scale, &x_pos, y_pos);
 					y_pos += px;
 					x_pos = 0.0;
 				}
 				else
 				{
-					DrawGlyph(&ed.ctx, g, scale, &x_pos, y_pos, cols[fb.tk.buffer[i]]);
+					DrawGlyph(g, scale, &x_pos, y_pos, cols[fb.tk.buffer[i]]);
 				}
 			}
 		}
diff --git a/src/editor/parsing.d b/src/editor/parsing.d
index 5384b87..591b7e7 100644
--- a/src/editor/parsing.d
+++ b/src/editor/parsing.d
@@ -618,7 +618,7 @@ ParseId(FlatBuffer* fb)
 	assert(t.start < t.end, "ParseId failure: start is lower or equal to end");
 }
 
-pragma(inline): bool
+pragma(inline) bool
 CheckEOL(u8 ch)
 {
 	return ch == 0x0D||
@@ -627,7 +627,7 @@ CheckEOL(u8 ch)
 				 ch == 0x0C;
 }
 
-pragma(inline): bool
+pragma(inline) bool
 CheckWhiteSpace(u8 ch)
 {
 	return ch == ' ' ||
diff --git a/src/editor/ui.d b/src/editor/ui.d
index 7812727..cfc4f07 100644
--- a/src/editor/ui.d
+++ b/src/editor/ui.d
@@ -7,17 +7,98 @@ import vulkan;
 
 import editor;
 
-enum BaseFlags : u32
+UIContext g_ui_ctx;
+const UIItem g_ui_nil_item;
+UIItem* g_UI_NIL;
+
+struct UIContext
 {
-	Clickable  = (1<<0),
-	ViewScroll = (1<<1),
-	DrawText   = (1<<2),
-	DrawBackground = (1<<3),
-	DrawBorder = (1<<4),
-	Resizeable = (1<<5),
-	Draggable = (1<<6),
+	HashTable!(UIHash, UIItem*) items;
+	Arena                       arena;
+	Renderer*                   rd;
+
+	UIBuffer                    buffer;
+
+	UIItem*                     root;
+
+	// UI builder state
+	FontAtlas                   atlas;
+	Vec4[4]                     bg_cols;
+	Vec4[4]                     border_cols;
+	UISize[A2D.max]             size_axes;
+	Rect                        padding;
+	u32                         tab_width;
+	f32                         text_scale;
 }
 
+struct UIBuffer
+{
+	MappedBuffer!(Vertex) mapped_vtx;
+	MappedBuffer!(u32)    mapped_idx;
+	Vertex[] vtx;
+	u32[]    idx;
+	u32      count;
+}
+
+enum CtxProperty
+{
+	None,
+	BackgroundColor,
+	BorderColor,
+	SizeKind,
+	SizeValue,
+	SizeStrictness,
+	FontAtlas,
+	AxisX,
+	AxisY,
+	Padding,
+	TextScale,
+	TabWidth,
+}
+
+alias CtxP = CtxProperty;
+
+enum Axis2D
+{
+	X,
+	Y,
+	Max,
+}
+
+alias A2D = Axis2D;
+
+enum UIRecurse 
+{
+	PostOrder,
+	PreOrder,
+}
+
+alias UIR = UIRecurse;
+
+enum UIProperties : u64
+{
+	Clickable  		 = (1<<0),
+	ViewScroll 		 = (1<<1),
+	DrawText   		 = (1<<2),
+	DrawBackground = (1<<3),
+	DrawBorder 		 = (1<<4),
+	Resizeable 		 = (1<<5),
+	Draggable 		 = (1<<6),
+}
+
+alias UIP = UIProperties;
+
+enum SizeKind : u64
+{
+	None,
+	Pixels,
+	TextContent,
+	PercentOfParent,
+	ChildrenSum,
+}
+
+alias SK = SizeKind;
+
 union Rect
 {
 	struct
@@ -38,87 +119,169 @@ alias UIHash = u64;
 
 alias UIPair = KVPair!(UIHash, UIItem*);
 
+struct UISize
+{
+	SizeKind kind;
+	f32      value;
+	f32      strictness;
+}
+
 struct UIItem
 {
-	BaseFlags flags;
-	Rect   		rect;
+	UIProperties    flags;
+
+	UIItem*         first;
+	UIItem*         last;
+	UIItem*         next;
+	UIItem*         prev;
+	UIItem*         parent;
+
+	UISize[A2D.max] size;
+	Rect            padding;
+	f32[A2D.max]    computed_rel_pos;
+	f32[A2D.max]    computed_size;
+	Rect            rect;
+	f32             text_scale;
 }
 
-struct UIContext
+struct UIKey
 {
-	HashTable!(UIHash, UIItem*) items;
-	Arena                       arena;
-
-	UIBuffer                    buffer;
-
-	Vec4[4]                     bg_cols;
-	Vec4[4]                     border_cols;
+	u8[] text;
+	u64  hash;
 }
 
 void
-Reset(UIContext* ctx)
+UIBeginFrame()
 {
-	ctx.buffer.count = 0;
-}
-
-UIContext
-CreateUIContext(Vertex[] vtx, u32[] idx)
-{
-	UIContext ctx = {
-		items: CreateHashTable!(UIHash, UIItem*)(16),
-		arena: CreateArena(MB(8)),
-		buffer: {
-			vtx: vtx,
-			idx: idx,
-		},
-	};
-
-	return ctx;
+	g_ui_ctx.buffer.count = 0;
 }
 
 void
-SetBgCols(UIContext* ctx, Vec4[4] cols)
+UIFrameSubmit()
 {
-	ctx.bg_cols = cols;
+	BindBuffers(g_ui_ctx.rd, &g_ui_ctx.buffer.mapped_idx, &g_ui_ctx.buffer.mapped_vtx);
+	DrawIndexed(g_ui_ctx.rd, 6, g_ui_ctx.buffer.count, 0);
 }
 
 void
-SetBorderCols(UIContext* ctx, Vec4[4] cols)
+InitUIContext(Renderer* rd)
 {
-	ctx.border_cols = cols;
+	g_UI_NIL = cast(UIItem*)&g_ui_nil_item;
+
+	auto vtx = CreateMappedBuffer!(Vertex)(rd, BT.Vertex, Vertex.sizeof * UI_COUNT);
+	auto idx = CreateMappedBuffer!(u32)(rd, BT.Index, u32.sizeof * UI_COUNT);
+
+	g_ui_ctx.root = g_UI_NIL;
+	g_ui_ctx.items = CreateHashTable!(UIHash, UIItem*)(16);
+	g_ui_ctx.arena = CreateArena(MB(8));
+	g_ui_ctx.rd = rd;
+	g_ui_ctx.buffer.mapped_vtx = vtx;
+	g_ui_ctx.buffer.mapped_idx = idx;
+	g_ui_ctx.buffer.vtx = vtx.data;
+	g_ui_ctx.buffer.idx = idx.data;
+}
+
+UIKey
+MakeKey(u8[] id)
+{
+	UIKey key;
+
+	u32 pos = 0;
+	u32 hash_count = 0;
+	for(u32 i = 0; i < id.length; i += 1)
+	{
+		if (hash_count == 2)
+		{
+			if (id[i] == '#')
+			{
+				hash_count += 1;
+			}
+
+			break;
+		}
+
+		if (id[i] == '#')
+		{
+			if (hash_count == 0)
+			{
+				pos = i;
+			}
+
+			hash_count += 1;
+		}
+	}
+
+	if (hash_count == 2)
+	{
+		key.text = id[0 .. pos];
+		key.hash = Hash(id);
+	}
+	else if (hash_count == 3)
+	{
+		key.text = id[0 .. pos];
+		key.hash = Hash(id[pos+hash_count .. $]);
+	}
+	else
+	{
+		key.text = id;
+		key.hash = Hash(id);
+	}
+
+	return key;
 }
 
 UIItem*
-Find(UIContext* ctx, u8[] id)
+Find(u8[] id)
 {
 	u64 hash = Hash(id);
-	Result!(UIItem*) result = ctx.items[hash];
+	Result!(UIItem*) result = g_ui_ctx.items[hash];
 	if (!result.ok)
 	{
-		result.value = Alloc!(UIItem)(&ctx.arena);
-		Push(&ctx.items, hash, result.value);
+		result.value = Alloc!(UIItem)(&g_ui_ctx.arena);
+		Push(&g_ui_ctx.items, hash, result.value);
 	}
 
 	return result.value;
 }
 
 bool
-UIWindow(UIContext* ctx, Rect rect, f32 border_px, u8[] text)
+UIWindow(Rect rect, f32 border_px, u8[] text)
 {
-	UIItem* item = Find(ctx, text);
-
-	DrawRect(ctx, rect.x0, rect.y0, rect.x1, rect.y1, 0.0, 0.0, 0.0, 0.0, ctx.bg_cols);
-	DrawRect(ctx, rect.x0, rect.y0, rect.x1, rect.y1, border_px, 0.0, 0.0, 0.0, ctx.border_cols);
+	UIItem* item = Find(text);
 
 	return false;
 }
 
-pragma(inline): void
-DrawGlyph(UIContext* ctx, Glyph* glyph, f32 scale, f32* x_pos, f32 y, Vec4 col = Vec4(1.0))
+f32
+CalcTextWidth(u8[] str)
+{
+	u32 tab_width = g_ui_ctx.tab_width;
+	Glyph* space = g_ui_ctx.atlas.glyphs.ptr + ' ';
+
+	f32 width;
+	for(u64 i = 0; i < str.length; i += 1)
+	{
+		Glyph* g = g_ui_ctx.atlas.glyphs.ptr + str.ptr[i];
+
+		if (g.ch == '\t')
+		{
+			width += space.advance * cast(f32)(tab_width);
+		}
+		else
+		{
+			width += g.advance;
+		}
+	}
+
+	return width * g_ui_ctx.text_scale;
+}
+
+pragma(inline) void
+DrawGlyph(Glyph* glyph, f32 scale, f32* x_pos, f32 y, Vec4 col = Vec4(1.0))
 {
 	if (glyph.atlas_left != glyph.atlas_right)
 	{
-		Vertex* v = ctx.buffer.vtx.ptr + ctx.buffer.count;
+		Vertex* v = g_ui_ctx.buffer.vtx.ptr + g_ui_ctx.buffer.count;
 
 		f32 r = glyph.plane_right * scale;
 		f32 l = glyph.plane_left * scale;
@@ -143,23 +306,18 @@ DrawGlyph(UIContext* ctx, Glyph* glyph, f32 scale, f32* x_pos, f32 y, Vec4 col =
 
 		v.texture = 1;
 
-		AddUIIndices(ctx);
+		AddUIIndices();
 	}
 
 	*x_pos += glyph.advance * scale;
 }
 
-pragma(inline) void
-DrawRect(UIContext* ctx, f32 p0_x, f32 p0_y, f32 p1_x, f32 p1_y, f32 border, f32 corner, f32 softness, f32 raised, Vec4 col)
-{
-	DrawRect(ctx, p0_x, p0_y, p1_x, p1_y, border, corner, softness, raised, [col, col, col, col]);
-}
-
+/*
 pragma(inline) void
 DrawRect(UIContext* ctx, f32 p0_x, f32 p0_y, f32 p1_x, f32 p1_y, f32 border, f32 corner, f32 softness, f32 raised, Vec4[4] cols)
 {
 	// Y reversed
-	Vertex* v = ctx.buffer.vtx.ptr + ctx.buffer.count;
+	Vertex* v = g_ui_ctx.buffer.vtx.ptr + g_ui_ctx.buffer.count;
 	v.dst_start.x = p0_x;
 	v.dst_start.y = p0_y;
 	v.dst_end.x = p1_x;
@@ -172,16 +330,115 @@ DrawRect(UIContext* ctx, f32 p0_x, f32 p0_y, f32 p1_x, f32 p1_y, f32 border, f32
 
 	AddUIIndices(ctx);
 }
+*/
 
 void
-AddUIIndices(UIContext* ctx)
+AddUIIndices()
 {
-	ctx.buffer.idx[0] = 0; 
-	ctx.buffer.idx[1] = 1; 
-	ctx.buffer.idx[2] = 2; 
-	ctx.buffer.idx[3] = 2; 
-	ctx.buffer.idx[4] = 1; 
-	ctx.buffer.idx[5] = 3; 
+	g_ui_ctx.buffer.idx[0] = 0; 
+	g_ui_ctx.buffer.idx[1] = 1; 
+	g_ui_ctx.buffer.idx[2] = 2; 
+	g_ui_ctx.buffer.idx[3] = 2; 
+	g_ui_ctx.buffer.idx[4] = 1; 
+	g_ui_ctx.buffer.idx[5] = 3; 
 
-	ctx.buffer.count += 1;
+	g_ui_ctx.buffer.count += 1;
 }
+
+bool
+Nil(UIItem* item)
+{
+	return item == null || item == g_UI_NIL;
+}
+
+UIItem*
+Recurse(alias mode)(UIItem* item, UIItem* root)
+{
+	UIItem* sibling, child, result = g_UI_NIL;
+
+	static if (mode == UIR.PostOrder) sibling = item.next; else sibling = item.prev;
+	static if (mode == UIR.PostOrder) child   = item.prev; else child   = item.last;
+
+	if (!Nil(child))
+	{
+		result = sibling;
+	}
+	else for(UIItem* i = sibling; !Nil(i) && i != root; i = i.parent)
+	{
+		static if (mode == UIR.PostOrder) sibling = i.next; else sibling = i.prev;
+
+		if (!Nil(sibling))
+		{
+			result = sibling;
+			break;
+		}
+	}
+
+	return result;
+}
+
+// Setter function in case I need to change to using a mutex
+pragma(inline) void
+SetProp(alias P, T)(T value)
+{
+	static if (is(T: Vec4[4]))
+	{
+		static if (0) {}
+		else static if (P == CtxP.BackgroundColor) { g_ui_ctx.bg_cols = value; }
+		else static if (P == CtxP.BorderColor)     g_ui_ctx.border_cols = value;
+		else static assert(false, "Unknown Property for type Vec4[4]");
+	}
+	else static if (is(T: SizeKind) && P == CtxP.SizeKind)
+	{
+		g_ui_ctx.size_kind = value;
+	}
+	else static if (is(T: UISize))
+	{
+		static if (0) {}
+		else static if (P == CtxP.AxisX) g_ui_ctx.size_axes[A2D.X] = value;
+		else static if (P == CtxP.AxisY) g_ui_ctx.size_axes[A2D.Y] = value;
+		else static assert(false, "Unknown Property for type UISize");
+	}
+	else static if (is(T: FontAtlas))
+	{
+		static if (0) {}
+		else static if (P == CtxP.FontAtlas) g_ui_ctx.atlas = value;
+		else static assert(false, "Unknown Property for type FontAtlas");
+	}
+	else static if (is(T: Rect))
+	{
+		static if (0) {}
+		else static if (P == CtxP.Padding) g_ui_ctx.padding = value;
+	}
+	else static if (is(T: f32))
+	{
+		static if (0) {}
+		else static if (P == CtxP.TextScale) g_ui_ctx.text_scale = value;
+		else static assert(false, "Unknown property for type f32");
+	}
+	else static if (is(T: u32))
+	{
+		static if (0) {}
+		else static if (P == CtxP.TabWidth) g_ui_ctx.tab_width = value;
+		else static assert(false, "Unknown property for type u32");
+	}
+	else static assert(false, "Unknown Type");
+}
+
+unittest
+{
+	{ // UI Key
+		u8[] str = cast(u8[])r"Test String##123";
+		UIKey key = MakeKey(str);
+
+		assert(key.text == cast(u8[])r"Test String");
+		assert(key.hash == Hash(str));
+
+		u8[] str1 = cast(u8[])r"Test String###123123";
+		key = MakeKey(str1);
+
+		assert(key.text == cast(u8[])r"Test String");
+		assert(key.hash == Hash(r"123123"));
+	}
+}
+