To reproduce, use the following code and minimize the child form:

    public partial class RadForm1 : Telerik.WinControls.UI.RadForm
    {
        public RadForm1()
        {
            InitializeComponent();
            this.IsMdiContainer = true;
 
            RadForm form = new RadForm();
            form.Text = "MDI Child";
            form.MdiParent = this;
            form.MinimumSize = new Size(800,600);
            form.Show(); 
        }
    }

To reproduce:

1. Create a new .NET 7 project and add a RadForm to it with a single control (e.g. RadButton).

2. Open the designer and have a look at the form's Size.

3. Move the button and save the changes

4. Close the designer and open it again.

Expected result: the RadForm's Size is unchanged

Actual result: the RadForm gets smaller, its height is reduced.

Follow the steps which are illustrated in the gif file:

1. Create new .NetFrameWork Telerik WinForm project

2. Set the MinSize of the RadForm1 to 300, 300

3. Set the MaxDize of the RadForm1 to 600, 600

4. Save the Form

5. Close the form

6. Build the project

7. Add new Telerik form, inherit from RadFrom1 via the Add New Item form and picking Inherited Form (Windows Forms).  When prompted, pick RadForm1.

8. Resize the new form

9. Save and Close the form.

10. Open RadForm1

11. Reset the Max Size

12. Save and Close RadForm1

13. Rebuild the project

14. Open the inherited form

Workaround: instead of adding an Inherited Form, add a Telerik RadForm. Then, change it to inherit from RadForm1:

Please run the sample project on 100% and 150% DPI scaling. You will notice that with 100% the shown form is centered to its parent, but with 150% it is shifted:

VS 2022, Telerik 2022.2.510, NET 6.0 (sample app is attached)

1. Creating sample Telerik WinForms App.
2. Add a RadTextBox
3. Load Event with code
radTextBox1.Text = this.Size.ToString();

4. Run the App
5. Close the App
6. Move the RadTextBox Control at design time.
In design, the height of the form is 2 pixels taller.
Run these steps in a loop. After a few hours of work, the form exceeds the size of the screen.

To reproduce:

1. Set your monitor DPI to 200%(or any order value different from 100%). You need to Log off(or restart) in order to apply correctly the new DPI settings.
2. Create a UserControl with some RadControls inside.
3. Add the UserControl at design time as a child control to a RadForm.
4. Run the RadForm and you will see that the controls inside the user control are scaled twice.

Workaround:

In the OnLoad method of RadForm do through all nested RadControls inside the UserControl and downscale them to the same DPI as the RadForm.

Updating from Version 2022.1.118 to 2022.1.222 breaks high dpi layout for existing dialogs at 150% DPI scaling:

Expected:

Actual:

Workaround: Use the MS Form

Workaround: set the RadRibbonFormBehavior1.AllowTheming property of the form to false

public class RadForm1
{
	public RadForm1()
	{
		InitializeComponent();

		this.RadRibbonFormBehavior1.AllowTheming = false;

	}
}

1. Create a new Form that inherits from RadForm and add some rad controls.
2. Checkin the file in your source control system
3. Open the form in design time will cause checkout

Steps to reproduce:
- add RadForm to the project 
- drop a RadRibbonBar to the project 
- when asked to use RadRibbonFormBehavior, confirm with Yes 
- check the form size (height) and close it 
- reopen it and the size is changed
- repeating the last two steps continues to increase the form height

Workaround:  change the parent of the form having the ribbon form behavior
 public partial class RadForm1 : CustomRadForm
    {
        public RadForm1()
        {
            InitializeComponent();
        }
    }

public class CustomRadForm : Telerik.WinControls.UI.RadForm
{
    public new FormControlBehavior FormBehavior
    {
        get
        {
            return (FormControlBehavior)typeof(RadFormControlBase)
                    .GetField("formBehavior", BindingFlags.Instance | BindingFlags.NonPublic)
                    .GetValue(this);
        }
        set
        {
            this.ResetFormBehavior(false);
            if (value != null)
            {
                Size clientSize = this.ClientSize;
                typeof(RadFormControlBase)
                    .GetField("formBehavior", BindingFlags.Instance | BindingFlags.NonPublic)
                    .SetValue(this, value);

                typeof(RadFormControlBase)
                    .GetMethod("PrepareBehavior", BindingFlags.Instance | BindingFlags.NonPublic)
                    .Invoke(this, new object[] { });

                this.RecreateHandle();

                this.ClientSize = clientSize;
            }
        }
    }
}

To reproduce:
- Create a RadForm with a public label in it. 
- Inherit the new form and change the label text.
- Open the second form at design time - the file status is changed to modified.

With the following property settings RadForm does not maximize in order to overlap the taskbar:
TopMost - true
WindowState = Maximized
FormBorderStyle = None

To reproduce:

1. Use the 2020.3.1020 Telerik version 

2. Show RadForm and set MinimumSize property

3. Double Click the Title Bar to maximize the form or click the Maximize button

4. Double Click the Title Bar again and see that no border is shown.

Thanks

To reproduce:
- Hide the border and change the BackColor of the form. 
- Dock a MenuStrip to the top. 
- You will notice that there are 2 pixels on the left and right sides of the menu. 

Project is attached as well.