Bug 291755 [Filters] Filters implementation and API cleanup
This bug is raised to track reviewing and cleanup of filters API and implementation.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ResourceFilterGroup.java
event.data = getFilterCopySelection();
			}
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see
		 * org.eclipse.swt.dnd.DragSourceListener#dragStart(org.eclipse.swt.
		 * dnd.DragSourceEvent)
		 */
		public void dragStart(DragSourceEvent event) {
			if (getFilterCopySelection().length == 0)
				event.doit = false;
		}
	}
	private static int getMinimumColumnWidth(TreeColumn column, int hint) {
		Assert.isNotNull(column);
		FontMetrics fontMetrics;
		GC gc = new GC(column.getParent());
		try {
			gc.setFont(column.getParent().getFont());
			fontMetrics = gc.getFontMetrics();
		} finally {
			gc.dispose();
		}
		return Math.max(hint, fontMetrics.getAverageCharWidth()
				* column.getText().length());
	}
	private void createButtonGroup(Composite parent) {
		Composite composite = new Composite(parent, SWT.NONE);