Bug 296800 [GlobalActions] UI build actions should not lock the workspace
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/GlobalBuildAction.java
boolean verifyBuildersAvailable(IProject[] roots) {
        try {
            for (int i = 0; i < roots.length; i++) {
                if (roots[i].isAccessible()) {
					if (roots[i].getDescription().getBuildSpec().length > 0) {
						return true;
					}
				}
            }
        } catch (CoreException e) {
        	StatusManager.getManager().handle(e, IDEWorkbenchPlugin.IDE_WORKBENCH);
            ErrorDialog
                    .openError(
                            getShell(),
                            IDEWorkbenchMessages.GlobalBuildAction_buildProblems,
                            NLS.bind(IDEWorkbenchMessages.GlobalBuildAction_internalError, e.getMessage()),
                            e.getStatus());
            return false;
        }
        return false;
    }
    /*
     * (non-Javadoc) Method declared on ActionFactory.IWorkbenchAction.
     * 
     * @since 3.0
     */
    public void dispose() {
        if (workbenchWindow == null) {
            
            return;