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
public void saveWidgetState() {
		if (coolItem == null)  return;
		
		
		CoolBar coolBar = coolItem.getParent();
		boolean isLastOnRow = false;
		int lastIndex = coolBar.getItemCount() - 1;
		int coolItemIndex = coolBar.indexOf(coolItem);
		int [] wrapIndicies = getAdjustedWrapIndices(coolBar.getWrapIndices());
		
		for (int row=wrapIndicies.length-1; row >= 0; row--) {
			if (wrapIndicies[row] <= coolItemIndex) {
				int nextRow = row + 1;
				int rowStartIndex = wrapIndicies[row];
				int nextRowStartIndex;
				if (nextRow > (wrapIndicies.length - 1) ) {
					nextRowStartIndex = lastIndex + 1;
				}else {
					nextRowStartIndex = wrapIndicies[nextRow];
				}
				 
				
				if (coolItemIndex == (nextRowStartIndex -1)) {
					isLastOnRow = true;
				}
				boolean isAloneOnRow = ((rowStartIndex == coolItemIndex) && isLastOnRow);
				break;
			 }
		 }