Bug 53582 Rebuild Project are not run in the background?
The "Build All" and "Rebuild All" actions are run in the background, but the "Build Project" and "Rebuild Project" actions aren't. This is not consistent and I was surprised to get a modal dialog when performing a "Rebuild Project".
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/WorkspaceAction.java
protected WorkspaceAction(Shell shell, String text) {
		super(text);
		if (shell == null) {
			throw new IllegalArgumentException();
		}
		this.shell = shell;
	}
	/**
	 * Opens an error dialog to display the given message.
	 * <p>
	 * Note that this method must be called from UI thread.
	 * </p>
	 *
	 * @param message the message
	 */
	void displayError(String message) {
		if (message == null) {
			message = IDEWorkbenchMessages.getString("WorkbenchAction.internalError"); 
		}
		MessageDialog.openError(shell, getProblemsTitle(), message);
	}
	/**
	 * Runs <code>invokeOperation</code> on each of the selected resources, reporting
	 * progress and fielding cancel requests from the given progress monitor.
	 *
	 * @param monitor a progress monitor
	 */
	final void execute(IProgressMonitor monitor) {
		
		List resources = getActionResources();