Bug 167191 [Markers] Add icon support for marker groupings
3.3 M3 - after a complete rebuild, I wanted to see if there were any errors - switched to the Problems view, which I had grouping by Java Problem Type - it showed several categories (all collapsed) - I couldn't tell at a glance if these represented errors or warnings -- I had to go and read the heading titles and expand a few to be comfortable that there weren't any errors - then I remembered that the counts are shown in the content description, and this showed 0 errors It would be nice if I could tell at a glance (visually, not just textually) what the severities are. Currently the icon used for category headings is a generic "tree of nodes" graphic. Could we associate a severity with a category and show the corresponding icon instead? Since JDT allows severities to be customized, we'd probably need to allow these to be specified programmatically, not just declaratively. Or perhaps the view could calculate the max severity in each category and show that.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/api/MarkerField.java
int width = gc.getFontMetrics().getAverageCharWidth();
		gc.dispose();
		return width;
	}
	/**
	 * Return the id for the receiver.
	 * 
	 * @return String
	 */
	public String getId() {
		return configurationElement
				.getAttribute(MarkerSupportConstants.ATTRIBUTE_ID);
	}
	/**
	 * Return the image for the receiver. By default return <code>null</code>.
	 * 
	 * @param item
	 * @return The image value of the object for this particular field to be
	 *         displayed to the user or <code>null<code>.
	 */
	public Image getImage(MarkerItem item) {
		return null;
	}
	/**
	 * Return the value for a marker.
	 * 
	 * @param marker
	 * @return String
	 */
	public String getMarkerValue(IMarker marker) {