Tables: another attempt at making contents not overlap the bottom and right border in a scrolling table. (#6765, #3752, #7428)

docs/CHANGELOG.txt

@@ -80,8 +80,9 @@ Other changes:
   payload over an already open tree node would incorrectly select it. (#7850)
 - MultiSelect+TreeNode: default open behavior is OpenOnDoubleClick + OpenOnArrow
   when used in a multi-select context without any OpenOnXXX flags set. (#7850)
-- Tables: revert 1.90 extension of bottom-most and right-most outer border offset by one.
-  This is not the right solution. (#6765, #3752)
+- Tables: fixes/revert a 1.90 change were outer border would be moved bottom and right
+  by an extra pixel + rework the change so that contents doesn't overlap the bottom and
+  right border in a scrolling table. (#6765, #3752, #7428)
 - InputText: allow callback to update buffer while in read-only mode. (imgui_club/#46)
 - InputText: fixed an issue programmatically refocusing a multi-line input which was just active. (#4761, #7870)
 - TextLink(), TextLinkOpenURL(): change mouse cursor to Hand shape when hovered. (#7885, #7660)

imgui_tables.cpp

@@ -460,16 +460,27 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     temp_data->HostBackupItemWidthStackSize = outer_window->DC.ItemWidthStack.Size;
     inner_window->DC.PrevLineSize = inner_window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
 
-    // Make left and top borders not overlap our contents by offsetting HostClipRect (#6765)
+    // Make borders not overlap our contents by offsetting HostClipRect (#6765, #7428, #3752)
     // (we normally shouldn't alter HostClipRect as we rely on TableMergeDrawChannels() expanding non-clipped column toward the
     // limits of that rectangle, in order for ImDrawListSplitter::Merge() to merge the draw commands. However since the overlap
     // problem only affect scrolling tables in this case we can get away with doing it without extra cost).
     if (inner_window != outer_window)
     {
+        // FIXME: Because inner_window's Scrollbar doesn't know about border size, since it's not encoded in window->WindowBorderSize,
+        // it already overlaps it and doesn't need an extra offset. Ideally we should be able to pass custom border size with
+        // different x/y values to BeginChild().
         if (flags & ImGuiTableFlags_BordersOuterV)
+        {
             table->HostClipRect.Min.x = ImMin(table->HostClipRect.Min.x + TABLE_BORDER_SIZE, table->HostClipRect.Max.x);
+            if (inner_window->DecoOuterSizeX2 == 0.0f)
+                table->HostClipRect.Max.x = ImMax(table->HostClipRect.Max.x - TABLE_BORDER_SIZE, table->HostClipRect.Min.x);
+        }
         if (flags & ImGuiTableFlags_BordersOuterH)
+        {
             table->HostClipRect.Min.y = ImMin(table->HostClipRect.Min.y + TABLE_BORDER_SIZE, table->HostClipRect.Max.y);
+            if (inner_window->DecoOuterSizeY2 == 0.0f)
+                table->HostClipRect.Max.y = ImMax(table->HostClipRect.Max.y - TABLE_BORDER_SIZE, table->HostClipRect.Min.y);
+        }
     }
 
     // Padding and Spacing
@@ -497,7 +508,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     table->InnerClipRect = (inner_window == outer_window) ? table->WorkRect : inner_window->ClipRect;
     table->InnerClipRect.ClipWith(table->WorkRect);     // We need this to honor inner_width
     table->InnerClipRect.ClipWithFull(table->HostClipRect);
-    table->InnerClipRect.Max.y = (flags & ImGuiTableFlags_NoHostExtendY) ? ImMin(table->InnerClipRect.Max.y, inner_window->WorkRect.Max.y) : inner_window->ClipRect.Max.y;
+    table->InnerClipRect.Max.y = (flags & ImGuiTableFlags_NoHostExtendY) ? ImMin(table->InnerClipRect.Max.y, inner_window->WorkRect.Max.y) : table->HostClipRect.Max.y;
 
     table->RowPosY1 = table->RowPosY2 = table->WorkRect.Min.y; // This is needed somehow
     table->RowTextBaseline = 0.0f; // This will be cleared again by TableBeginRow()
@@ -1249,7 +1260,7 @@ void ImGui::TableUpdateLayout(ImGuiTable* table)
     if (table->Flags & ImGuiTableFlags_NoClip)
         table->DrawSplitter->SetCurrentChannel(inner_window->DrawList, TABLE_DRAW_CHANNEL_NOCLIP);
     else
-        inner_window->DrawList->PushClipRect(inner_window->ClipRect.Min, inner_window->ClipRect.Max, false);
+        inner_window->DrawList->PushClipRect(inner_window->InnerClipRect.Min, inner_window->InnerClipRect.Max, false);
 }
 
 // Process hit-testing on resizing borders. Actual size change will be applied in EndTable()