Bug 300855 Do not allow Path Variables with empty location
HEAD I'm able to create a path variable without location. Next, when I want to edit the variable, Edit Variable dialog opens with error saying "You must provide a file or folder path as variable value.". I guess I should not be able to create such variable in the first place.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariableDialog.java
super.configureShell(shell);
        if (operationMode == NEW_VARIABLE)
            shell.setText(IDEWorkbenchMessages.PathVariableDialog_shellTitle_newVariable);
        else if (operationMode == EXISTING_VARIABLE)
            shell.setText(IDEWorkbenchMessages.PathVariableDialog_shellTitle_existingVariable);
        else
            shell.setText(IDEWorkbenchMessages.PathVariableDialog_shellTitle_editLocation);
    }
    /**
     * Creates and returns the contents of this dialog (except for the button bar).
     * 
     * @see org.eclipse.jface.dialogs.TitleAreaDialog#createDialogArea
     */
    protected Control createDialogArea(Composite parent) {
        
        Composite parentComposite = (Composite) super.createDialogArea(parent);
        initializeDialogUnits(parentComposite);
        
        
        Composite contents = createComposite(parentComposite);
         
        createWidgets(contents);
        
        if (type == EXISTING_VARIABLE) {
            nameEntered = locationEntered = true;
            validateVariableValue();
        }
        Dialog.applyDialogFont(parentComposite);
        
        return contents;