BeginPopupContextItem(): Skip processing when SkipItems is set as LastItemId is unreliable and we assert when it is zero. + Minor comments on columns.

imgui.cpp

@@ -7229,6 +7229,8 @@ void ImGui::EndPopup()
 bool ImGui::BeginPopupContextItem(const char* str_id, int mouse_button)
 {
     ImGuiWindow* window = GImGui->CurrentWindow;
+    if (window->SkipItems)
+        return false;
     ImGuiID id = str_id ? window->GetID(str_id) : window->DC.LastItemId; // If user hasn't passed an ID, we can use the LastItemID. Using LastItemID as a Popup ID won't conflict!
     IM_ASSERT(id != 0);                                                  // You cannot pass a NULL str_id if the last item has no identifier (e.g. a Text() item)
     if (IsMouseReleased(mouse_button) && IsItemHovered(ImGuiHoveredFlags_AllowWhenBlockedByPopup))
@@ -8435,7 +8437,8 @@ void ImGui::NextColumn()
     columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
     if (++columns->Current < columns->Count)
     {
-        // New column (columns 1+ cancels out IndentX)
+        // Columns 1+ cancel out IndentX
+        // FIXME-COLUMNS: Unnecessary, could be locked?
         window->DC.ColumnsOffset.x = GetColumnOffset(columns->Current) - window->DC.Indent.x + g.Style.ItemSpacing.x;
         window->DrawList->ChannelsSetCurrent(columns->Current + 1);
     }
@@ -8452,7 +8455,7 @@ void ImGui::NextColumn()
     window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
     window->DC.CurrLineTextBaseOffset = 0.0f;
 
-    PushColumnClipRect(columns->Current);
+    PushColumnClipRect(columns->Current);     // FIXME-COLUMNS: Could it be an overwrite?
     PushItemWidth(GetColumnWidth() * 0.65f);  // FIXME-COLUMNS: Move on columns setup
 }