Bug 273489 [Mac] We should not nest sheets
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariableDialog.java
validateVariableValue();
        }
        Dialog.applyDialogFont(parentComposite);
        
        return contents;
    }
    /**
     * Creates and configures this dialog's main composite.
     * 
     * @param parentComposite parent's composite
     * @return this dialog's main composite
     */
    private Composite createComposite(Composite parentComposite) {
        
        Composite contents = new Composite(parentComposite, SWT.NONE);
        contents.setLayout(new GridLayout(3, false));
        contents.setLayoutData(new GridData(GridData.FILL_BOTH));
        if (newVariable) {
			setTitle(IDEWorkbenchMessages.PathVariableDialog_dialogTitle_newVariable);
		} else {
			setTitle(IDEWorkbenchMessages.PathVariableDialog_dialogTitle_existingVariable);
		}
        setMessage(standardMessage);
        return contents;
    }
    /**
     * Creates widgets for this dialog.
     * 
     * @param contents the parent composite where to create widgets
     */