Bugfix decorated window on windows - clickable components inside title area should work now

[MFlisar]

Idea

Place a background composable behind the title content that handles all windows draggable header related stuff. This way, everything inside the title bar is placed on top of the composable that forwards the events to the draggable header.

Issues this solves

when clicking a dropdown menu in the title bar, the popup did not pop up until the next mouse move => fixed

TODO

• I added a Box around the title content, apply the modifier to it instead of the title bar composable and place the title bar composable inside the box with a simple fillMaxSize Modifier - I'm pretty sure it does not change anything, still, it needs to be tested on mac and linux as well once
• the macos implementation does use customTitleBarMouseEventHandler as well - it may be necessary to use the same fix there? I don't know, I don't have a mac and I don't know if the mac has the same issues
• for the sake of minimal adjustments I kept the customTitleBarMouseEventHandler as is (also because I don't know how it is used on mac) - it may be possible to simplifiy it like following as there is no need to try to detect if we are over a user control or not anymore because of the layerig of the background composable and the content.

internal fun Modifier.customTitleBarMouseEventHandler(titleBar: CustomTitleBar): Modifier =
    pointerInput(Unit) {
        val currentContext = currentCoroutineContext()
        awaitPointerEventScope {
            while (currentContext.isActive) {
                awaitPointerEvent(PointerEventPass.Main)
                titleBar.forceHitTest(false)
            }
        }
    }

Fix #368

[rock3r]

Hi, I ported & tested the change on macOS and it doesn't seem to make any difference with the previous behaviour. Dragging the title bar sometimes works, and sometimes it doesn't. I can't figure out what the reason is... there doesn't seem to be much of a pattern. I also tried mucking around a bit with the code to see if I could get it to work, but it still has the same issue. This needs some more investigation...

[rock3r]

@MFlisar I pushed the tweaks I did locally to a PR on your fork, if you want to incorporate them: MFlisar#1

[MFlisar]

Can you tell me if the click behavior on the dropdown menu is the same as for me (before and after)? If so, can you reproduce the improvement in this case?

Actually I can't see any issues with drag&drop, it behaves as it should for me when I play around for a few minutes.