Bug: Title Bar Covers Resize Hit-Test Area – Cannot Resize Window

[blisx2]

Describe the bug

When I use a custom titlecar, the window edges underneath the title bar area no longer respond to resize operations. However, if I remove the title bar, window edge resizing works correctly.

To Reproduce

Run the application.
Try to resize the window from the edges, especially under the title bar area.
Resizing fails where the title bar overlaps the edge.

Expected behavior

The window should still be resizable from the edges, even when a custom titlebar is used.

Screenshots

OS version

Win11

.NET version

.NET 8

WPF-UI NuGet version

4.0.0

Additional context

No response

[LoganNickersonAllient]

This bug can be fixed by accounting for the resize border in this click handler. After it accounts for the window control buttons, a switch statement controls what happens to uncaught clicks. I have coded a fix for this behavior, but looking at all the open pull requests from years ago, I'm not going to bother adding another unless someone specifically requests it.

If anyone needs a hack that works right now, set the TrailingContent property to a rectangle with a height equal to SystemParameters.WindowResizeBorderThickness, and make sure it is vertically aligned to the top. You'll need a converter because that value is a Thickness struct.

The code:

wpfui/src/Wpf.Ui/Controls/TitleBar/TitleBar.cs

Line 685 in 7f0dd18

switch (message)