Bug 41500 call hierarchy: history dialog, button enablement incorrect [call hierarchy]
20030806 in the history dialog, the 'Remove' button is enabled when nothing is selected and disabled when everything is selected both are wrong
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/HistoryListAction.java
* @see Dialog#createDialogArea(Composite)
		 */
		protected Control createDialogArea(Composite parent) {
			initializeDialogUnits(parent);
			
			Composite composite= (Composite) super.createDialogArea(parent);
			
			Composite inner= new Composite(composite, SWT.NONE);
			inner.setLayoutData(new GridData(GridData.FILL_BOTH));
			LayoutUtil.doDefaultLayout(inner, new DialogField[] { fHistoryList }, true, 0, 0);
			LayoutUtil.setHeightHint(fHistoryList.getListControl(null), convertHeightInCharsToPixels(12));
			LayoutUtil.setHorizontalGrabbing(fHistoryList.getListControl(null));
			applyDialogFont(composite);		
			return composite;
		}
		/**
		 * Method doCustomButtonPressed.
		 */
		private void doCustomButtonPressed() {
			fHistoryList.removeElements(fHistoryList.getSelectedElements());
		}
		
		private void doDoubleClicked() {
			if (fHistoryStatus.isOK()) {
				okPressed();
			}
		}
		
		
		private void doSelectionChanged() {