Windows 11 theme RadGridView Issue

[Ict]

I'm converting my application to use the Windows 11 theme and I noticed an issue that sometimes pops up with the RadGridView control.
When closing a details section of a row (click on the minus button to close the row again) the lines suddenly jump down and show a bit white space.

I didn't have the issue before I switched to the new theme. (before we were using the Office 2016 theme)
Currently I have no clue why it's happening or where I should start looking. When I scroll or click on the plus button to open row details it goes back to normal.

Anybody experienced something similar before?

[Martin Ivanov]

Can you try the latest version of Telerik UI for WPF and see if the issue still occurs? Also, you can set the GroupRenderMode property of RadGridView to Flat. 

If these ideas don't help, can you send over a project reproducing the issue?

[Ict]

I did some digging and when I put "EnableRowVirtualization" to False, it seems to work as expected. But I'm afraid that this will have a negative impact on performance.

[Martin Ivanov]

Yes, it is highly possible to fix this type of issues when disabling the UI virtualization, but I wouldn't recommend this since it is going to hit the performance, as you already noticed.

Did you have the chance to try the Flat GroupRenderMode?

[Ict]

I already had GroupRenderMode set to Flat

[Martin Ivanov]

In that case can you send over some code showing your setup or a runnable project that I can test?

[Ict]

What's the easiest way to send you some parts of the code? Isolating the problem is not easy. Part of a quit big solution and the issue occurs only on a few of our most complex screens. 

[Martin Ivanov]

The most reliable approach would be to isolate the issue in a separate project. If you can't do that, you can send over the XAML code related to RadGridView and also any code behind and view models used with it. This will allow me to try isolating the issue on my side.

[Ict]

I've attached a zip file with a few of our files. You'll see why it's difficult to extract it from our codebase :-) But anyway, thanks for trying to help me out. It's a rather large grid with different tabs on the detail level which also include grids. So maybe that's where the issue lies.

[Martin Ivanov]

Thank you for the code. I will check it out and get back to you later today.

[Martin Ivanov]

I've checked the code, but a big amount of code required for the setup is missing, so I couldn't test it. This is why I have gone through the code, but there isn't anything obvious that I can see. I also isolated what I could (mostly the Xaml with some dummy classes) in order to see if I can reproduce the issue based on the layout. Still the same result - no issue is presented. Maybe you can take a look at the attached project and see if you can come up with some ideas on what should be added there.

Also, you can try removing parts of the code related to RadGridView in order to try isolating which part exactly is causing the troublesome behavior. And one more thing is to check if there is any code (like calling of the Rebind method of the GridView or changes in its size) in an event handler attached to your RadGridView instance (if you have any handlers, of course).

 

[Martin Ivanov]

It's me again. Today we got a report about a very similar issue as yours with a runnable example that reproduces it and we have logged a new issue in the feedback portal. You can take a look at it: https://feedback.telerik.com/wpf/1582935-gridview-empty-space-between-the-rows-appears-when-gridview-is-hosted-in-radexpander-and-the-row-details-gets-collapsed

Also, you can try the workarounds suggested in the feedback item. The most promising solution would be to replace the RadExpander control with a native Expander. Also, you can make sure that the row's content height don't exceed the default row height of 25 pixels and see if this helps.

[Ict]

Setting the GroupRenderMode to Nested seems to do the trick. Is there a possible side-effect? And is there going to be a fix issued for this problem? Seems to be related to the Windows 11 layout (at least from what I see)

[Martin Ivanov]

The issue that I have posted seems to reproduce regardless of the theme. In this case the theme was the default Office_Black. However, I can't tell if this the same as your case.

I don't promise anything, about a timeframe for a fix, but I can suggest you to follow the feedback item in order to get notifications when its status changes.

The GroupRenderMode works pretty stable, but it has some issue here and there. Anyway, I can't point exactly what may happen, but it is more probable that you don't hit anything there. Anyway if you do, you can share it here.