Bug 260892 [CellEditors] NPE from ColumnViewerEditor caused by showing a dialog during modify
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewerEditor.java
return false;
				}
				setLayoutData(cellEditor.getLayoutData());
				setEditor(control, (Item) cell.getItem(), cell.getColumnIndex());
				cellEditor.setFocus();
				if (cellEditor.dependsOnExternalFocusListener()) {
					if (focusListener == null) {
						focusListener = new FocusAdapter() {
							public void focusLost(FocusEvent e) {
								applyEditorValue();
							}
						};
					}
					control.addFocusListener(focusListener);
				}
				mouseListener = new MouseAdapter() {
					public void mouseDown(MouseEvent e) {
						
						
						if (shouldFireDoubleClick(activationTime, e.time, activationEvent) && e.button == 1) {
							control.removeMouseListener(mouseListener);
							cancelEditing();
							handleDoubleClickEvent();
						} else if (mouseListener != null) {
							control.removeMouseListener(mouseListener);
						}
					}
				};
				if (activationTime != 0
						&& (feature & KEEP_EDITOR_ON_DOUBLE_CLICK) == 0) {