Bug 273489 [Mac] We should not nest sheets
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariableDialog.java
}
        } else {
            IStatus status = pathVariableManager.validateName(variableName);
            if (!status.isOK()) {
                
                newValidationStatus = IMessageProvider.ERROR;
                message = status.getMessage();
            } else if (namesInUse.contains(variableName)
                    && !variableName.equals(originalName)) {
                
                message = IDEWorkbenchMessages.PathVariableDialog_variableAlreadyExistsMessage;
                newValidationStatus = IMessageProvider.ERROR;
            } else {
                allowFinish = true;
            }
        }
        
        
        if (validationStatus == IMessageProvider.NONE
                || newValidationStatus == IMessageProvider.ERROR) {
            validationStatus = newValidationStatus;
            validationMessage = message;
        }
         
        
        if (allowFinish == false) {
			setMessage(validationMessage, validationStatus);
		}
        return allowFinish;
    }