* Bug in GTK.  When using fixed-height-mode on versions before 2.6.3,
* Bug in GTK.  When using fixed-height-mode,
void clear () {	if (parent.currentItem == this) return;	if (cached || (parent.style & SWT.VIRTUAL) == 0) {		int columnCount = OS.gtk_tree_model_get_n_columns (parent.modelHandle);		for (int i=Tree.CHECKED_COLUMN; i<columnCount; i++) {			OS.gtk_tree_store_set (parent.modelHandle, handle, i, 0, -1);		}		/*		* Bug in GTK.  When using fixed-height-mode on versions before 2.6.3,		* row changes do not cause the row to be repainted.  The fix is to		* invalidate the row when it is cleared.		*/		if ((parent.style & SWT.VIRTUAL) != 0) {			if (OS.GTK_VERSION >= OS.VERSION (2, 3, 2) && OS.GTK_VERSION < OS.VERSION (2, 6, 3)) {				if ((OS.GTK_WIDGET_FLAGS (parent.handle) & OS.GTK_REALIZED) != 0) {					int /*long*/ parentHandle = parent.handle;					int /*long*/ path = OS.gtk_tree_model_get_path (parent.modelHandle, handle);					// TODO scrolling affects rect					GdkRectangle rect = new GdkRectangle ();					OS.gtk_tree_view_get_cell_area (parentHandle, path, 0, rect);					OS.gtk_tree_path_free (path);					int /*long*/ window = OS.gtk_tree_view_get_bin_window (parentHandle);					rect.x = 0;					rect.width = OS.GTK_WIDGET_WIDTH (parentHandle);					OS.gdk_window_invalidate_rect (window, rect, false);				}			}		}			}	cached = false;	font = null;	cellFont = null;}