Columns: First first column appearing wider than others (#1266)

imgui.cpp

@@ -9416,7 +9416,7 @@ float ImGui::GetColumnOffset(int column_index)
 
     IM_ASSERT(column_index < window->DC.ColumnsData.Size);
     const float t = window->DC.ColumnsData[column_index].OffsetNorm;
-    const float x_offset = window->DC.ColumnsMinX + t * (window->DC.ColumnsMaxX - window->DC.ColumnsMinX);
+    const float x_offset = ImLerp(window->DC.ColumnsMinX, window->DC.ColumnsMaxX, t);
     return (float)(int)x_offset;
 }
 
@@ -9518,7 +9518,7 @@ void ImGui::Columns(int columns_count, const char* id, bool border)
     window->DC.ColumnsShowBorders = border;
 
     const float content_region_width = (window->SizeContentsExplicit.x != 0.0f) ? window->SizeContentsExplicit.x : window->Size.x;
-    window->DC.ColumnsMinX = window->DC.IndentX; // Lock our horizontal range
+    window->DC.ColumnsMinX = window->DC.IndentX - g.Style.ItemSpacing.x; // Lock our horizontal range
     window->DC.ColumnsMaxX = content_region_width - window->Scroll.x - ((window->Flags & ImGuiWindowFlags_NoScrollbar) ? 0 : g.Style.ScrollbarSize);// - window->WindowPadding().x;
     window->DC.ColumnsStartPosY = window->DC.CursorPos.y;
     window->DC.ColumnsCellMinY = window->DC.ColumnsCellMaxY = window->DC.CursorPos.y;