Bug 84446 OperationHistory should protect itself better against runtime exceptions
Since clients of the history might rely on getting certain events even if a operation causes runtime exceptions (for example listeners) the history should protect itself better agains runtime exceptions. This envloves: - listeners causing runtime exceptions in the call back - Operation execution causing runtime exceptions. In this case listeners must be informed as well.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/AbstractOperation.java
/**
	 * Construct an operation that has the specified label.
	 * 
	 * @param label -
	 *            the label to be used for the operation.
	 */
	public AbstractOperation(String label) {
		fLabel = label;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#addContext(org.eclipse.core.commands.operations.IUndoContext)
	 */
	public void addContext(IUndoContext context) {
		if (!fContexts.contains(context)) {
			fContexts.add(context);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IUndoableOperation#canExecute()
	 */
	public boolean canExecute() {
		return true;
	}
	/*
	 * (non-Javadoc)
	 *