Bug 216811 [Markers] ExtendedMarkersView#setFocus doesn't
The result is that focus is lost if you drag the view to another stack... The most common implementation seems to be 'viewer.getControl().setFocus()... To test: select an element in the Problems or Tasks view. Drag the view to a new location (could be in an existing stack or a new one) notice that while the view is the active view the arrow keys don't navigate...
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
/**
	 * MarkerSelectionEntry is a cache of the values for a marker entry.
	 * 
	 * @since 3.4
	 * 
	 */
	final class MarkerSelectionEntry {
		Object[] cachedValues;
		MarkerSelectionEntry(MarkerItem item) {
			MarkerField[] fields = builder.getVisibleFields();
			cachedValues = new Object[fields.length];
			for (int i = 0; i < fields.length; i++) {
				cachedValues[i] = fields[i].getValue(item);
			}
		}
		/**
		 * Return whether or not the entry is equivalent to the cached state.
		 * 
		 * @param item