Telerik WinForms 2025.Q2 radForm C# resize problem

[ALEXANDRU]

Hello Telerik team,

After upgrading to Telerik WinForms 2025.Q2, I’ve encountered several issues related to form layout rendering at runtime, which were not present before the update.

Enviroment:

.NET Framework 4.8.1
RadForm (not RadRibbonForm)
DPI awareness set to system in app.manifest
AutoScaleMode = Dpi

Could you please confirm if these layout behaviors are intentional in 2025.2 and whether there is an official workaround or setting to restore the previous behavior?

Thank you!

[runningnet]

We are encountering the same issue too.

[Blas]

I have the same problem after upgrading, but it only happens when I show a radform in modal mode.

 

[Nadya | Tech Support Engineer]

Hello,

David and Blas, I have already responded to the separate tickets you submitted. Let's continue our discussion there. 

[Nadya | Tech Support Engineer]

Hello, ALEXANDRU,

I am sorry to hear that you encountered an issue after upgrading to the latest 2025 Q2 version.

We have introduced some changes regarding RadForm in our 2025.2.520 version. However, in order to determine if there is an issue in our latest version, we should isolate the issue first and make further investigation. Can you help me replicating your problem?

It would be of great help if you can mimic your setup that can reproduce the problem with the latest version. Thus, we should be able to make an adequate analysis and investigate in more depth.

Looking forward to your reply.

Regards,
Nadya | Tech Support Engineer
Progress Telerik

[ALEXANDRU]

Hello Nadya,

I have attached a project that exemplifies the problem I faced, after updating to version 2025.2.520.462.

Thank you!

[Nadya | Tech Support Engineer]

Hello, ALEXANDRU,

The provided project is greatly appreciated. I updated your Telerik Points as a gesture of gratitude for your help in reproducing the issue.

Based on it, and also on the information provided by @Blas and @David, we were able to isolate a problem with ClientSize on inherited RadForms. This seems to be a regression related to another bug that we fixed in our latest Q2 2025 version. Please accept our apologies for this undesired behavior. We will do our best to fix this as soon as possible and include the fix in a future preview version.

This issue is already logged in our feedback portal: RadForm: ClientSize on inherited RadForm is broken 

I would like to let you know that we are already investigating it. However, we need more time to make a deeper investigation and testing until we announce the fix. Until then, we managed to find a workaround for you. The workaround is to override the SetClientSize method of the inherited RadForm - you can see the whole solution in the feedback item. Note, this workaround should not break the existing behavior of the other RadForms, so you can safely use it on your inherited forms.

public partial class RadForm2 : RadForm1
{
    protected override void SetClientSizeCore(int x, int y)
    {
        base.SetClientSizeCore(x, y);

        if ((!this.IsLoaded || !this.IsHandleCreated) &&
            this.IsInitialized)
        {
            MethodInfo mi = typeof(Form).GetMethod("SetClientSizeCore", BindingFlags.NonPublic | BindingFlags.Instance);
            if (mi != null)
            {
                IntPtr ptr = mi.MethodHandle.GetFunctionPointer();
                Action<int, int> baseSetClientSizeCore = (Action<int, int>)Activator.CreateInstance(
                    typeof(Action<int, int>), this, ptr);

                baseSetClientSizeCore.Invoke(x, y);
            }
        }
    }
}

I also updated your project to reflect the suggested changes. You can see the result of your Derivated RadForm in the attached picture. The updated project is also attached. 

I hope this helps. Please let me know if I can assist you further.