Bug 48452 Widget is disposed while closing cool bar
This is the problem that is occurring in the nightly builds. There is something happening where a cool bar is attempting to layout disposed cool bar items.
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ToolBarContributionItem.java
return toolBarManager;
	}
	/** 
	 * Returns a consistent set of wrap indices. The return value
	 * will always include at least one entry and the first entry will 
	 * always be zero.  CoolBar.getWrapIndices() is inconsistent 
	 * in whether or not it returns an index for the first row.
	 */
	private int[] getAdjustedWrapIndices(int[] wraps) {
		int[] adjustedWrapIndices;
		if (wraps.length == 0) {
			adjustedWrapIndices = new int[] { 0 };
		} else {
			if (wraps[0] != 0) {
				adjustedWrapIndices = new int[wraps.length + 1];
				adjustedWrapIndices[0] = 0;
				for (int i = 0; i < wraps.length; i++) {
					adjustedWrapIndices[i + 1] = wraps[i];
				}
			} else {
				adjustedWrapIndices = wraps;
			}
		}
		return adjustedWrapIndices;
	}
	
	/*
	 * (non-Javadoc)
	 * @see org.eclipse.jface.action.IContributionItem#fill(org.eclipse.swt.widgets.CoolBar, int)
	 */