LibGUI: Make inline editing work in ColumnsView

All it took was overriding content_rect() :^)

Libraries/LibGUI/ColumnsView.cpp

@@ -305,8 +305,8 @@ void ColumnsView::move_cursor(CursorMovement movement, SelectionUpdate selection
             if (model.is_valid(cursor_index()))
                 push_column(cursor_index());
             update();
-        break;
+            break;
-    }
+        }
     default:
         break;
     }
@@ -328,4 +328,19 @@ void ColumnsView::keydown_event(KeyEvent& event)
     AbstractView::keydown_event(event);
 }
 
+Gfx::IntRect ColumnsView::content_rect(const ModelIndex& index) const
+{
+    if (!index.is_valid())
+        return {};
+
+    int column_x = 0;
+    for (auto& column : m_columns) {
+        if (column.parent_index == index.parent())
+            return { column_x, index.row() * item_height(), column.width, item_height() };
+        column_x += column.width;
+    }
+
+    return {};
+}
+
 }

Libraries/LibGUI/ColumnsView.h

@@ -38,6 +38,7 @@ public:
     void set_model_column(int column) { m_model_column = column; }
 
     virtual ModelIndex index_at_event_position(const Gfx::IntPoint&) const override;
+    virtual Gfx::IntRect content_rect(const ModelIndex&) const override;
 
 private:
     ColumnsView();