Bug 260892 [CellEditors] NPE from ColumnViewerEditor caused by showing a dialog during modify
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewerEditor.java
final int activationTime;
				if (timeout != 0) {
					activationTime = activationEvent.time + timeout;
				} else {
					activationTime = 0;
				}
				if (editorActivationListener != null
						&& !editorActivationListener.isEmpty()) {
					Object[] ls = editorActivationListener.getListeners();
					for (int i = 0; i < ls.length; i++) {
						((ColumnViewerEditorActivationListener) ls[i])
								.beforeEditorActivated(activationEvent);
						
						if (activationEvent.cancel) {
							return false;
						}
					}
				}
				updateFocusCell(cell, activationEvent);
				cellEditor.addListener(cellEditorListener);
				part.getEditingSupport().initializeCellEditorValue(cellEditor,
						cell);
				
				
				
				
				
				final Control control = cellEditor.getControl();
				cellEditor.activate(activationEvent);
				if (control == null) {