Bug 232196 Workspace chooser cancel button results in crash on Linux
Hitting cancel on the Workspace Launcher in the Linux Motif build, I get a crash (attaching logfile).
bundles/org.eclipse.ui.ide.application/src/org/eclipse/ui/internal/ide/application/IDEApplication.java
*         otherwise
     */
    private boolean checkInstanceLocation(Shell shell) {
        
        Location instanceLoc = Platform.getInstanceLocation();
        if (instanceLoc == null) {
            MessageDialog
                    .openError(
                            shell,
                            IDEWorkbenchMessages.IDEApplication_workspaceMandatoryTitle,
                            IDEWorkbenchMessages.IDEApplication_workspaceMandatoryMessage);
            return false;
        }
        
        if (instanceLoc.isSet()) {
            
            
            if (!checkValidWorkspace(shell, instanceLoc.getURL())) {
				return false;
			}
            
            
            try {
                if (instanceLoc.lock()) {
                    writeWorkspaceVersion();
                    return true;
                }