Vaadin Dialog Size Issue: Shrinking When Dragged Right

Are you experiencing a frustrating issue with your Vaadin dialogs, where they shrink in size when dragged to the right side of the view? This is a known problem in Vaadin versions 24.8 and 24.9, and it can significantly impact the user experience. The good news is that this issue seems to be resolved in Vaadin 25 with base styles. Let's dive deeper into this problem, explore its causes, and examine potential solutions and workarounds.

The Problem: Dialog Shrinkage on Rightward Drag

When developing web applications with Vaadin, you often use Dialog components to display important information or collect user input. The ability to drag these dialogs around the screen is a convenient feature for users. However, in Vaadin 24.x, a peculiar bug emerges: when a dialog is dragged towards the right edge of the screen, it inexplicably shrinks in size. This behavior is inconsistent, as dragging the dialog to the left side does not trigger the same size reduction. This inconsistent behavior disrupts the expected user experience and makes the application feel less polished and reliable.

Imagine a scenario where a user is trying to position a dialog containing crucial information on the right side of the screen, only to have it unexpectedly shrink, potentially obscuring its contents or making it difficult to interact with. This can lead to frustration and a negative perception of your application. The fact that this issue is specific to the right-side drag adds to the confusion, as users may not immediately understand why the dialog is behaving this way.

This behavior is related to how the dialog component interacts with the browser's rendering engine and the layout constraints applied during the drag operation. The exact cause is complex and often involves a combination of factors, including the component's internal styles, the way the browser handles drag events, and the positioning of the dialog relative to the viewport. Understanding the root cause requires detailed analysis of the Vaadin framework's source code and the browser's rendering behavior, making it challenging to pinpoint the exact source of the problem. While it may not be feasible to immediately fix it, awareness of the issue and available workarounds can help mitigate its impact on your users.

Reproducing the Issue: Steps and Code

To effectively address this issue, it's crucial to be able to reproduce it consistently. Fortunately, the provided minimal reproducible example (MRE) makes it straightforward to replicate the problem. Here’s a breakdown of the steps and the code to help you recreate the scenario:

Step-by-Step Reproduction

1. Set up your environment: Ensure you have a Vaadin 24.8 or 24.9 application running. A basic setup with the necessary Vaadin dependencies will suffice. If you're using an older version, the issue may not be present, so use the versions specified in the issue. Make sure that you use a browser to run the application.
2. Create a simple view: Create a new view (e.g., a class annotated with @Route) in your Vaadin application. This view will contain the dialog and the button to trigger it. If you have experience with other Vaadin components, then that will be helpful for you.
3. Implement the dialog: Implement the Dialog component within the view. The implementation should include a dialog with a header, content, and footer. Add a draggable feature using the setDraggable(true) method. Use this to ensure that you can move the dialog.
4. Add content: Within the dialog's layout, add some content, such as text, form fields, or any other relevant components. This content will represent what is displayed in the dialog. Also, make sure that the content is related to the dialog, to properly reflect the issues.
5. Add a button to show the dialog: Include a button that, when clicked, opens the dialog. This will allow users to interact with the dialog. Make sure the button is properly displayed on the main view.
6. Test the drag behavior: Run the application and open the dialog. Then, attempt to drag the dialog to the right side of the screen. Observe whether the dialog shrinks. Test the left and right sides to see whether the behavior is consistent.
7. Compare results: If the dialog shrinks when dragged to the right in Vaadin 24.x, but not in Vaadin 25 (with base styles), you have successfully reproduced the issue. This allows you to verify that the issue exists in the specified versions. You will also see whether the issue has been resolved in Vaadin 25.

The MRE Code

The provided code snippet is a minimal example that can be used to replicate the issue. This makes the reproduction process easier, as you don't have to start from scratch. Below is a breakdown of the key parts of the code:

@Route(