Can not place widget on the NewApplication window (the preview of the app window)

[Patrik Svestka]

When I try to place a widget e.g. button I'm getting now only warning at the ST/X Launcher:
DisplaySurface? [warning]: lost expose event
DisplaySurface? [warning]: lost expose event

By random I succeed by placing the button but this behavior is extremely annoying as you have to "fight" with the application for the placement.

[Jan Vrany]

Two observations:

• Does NOT happen on Linux, looks like a Windows-specific problem (explains why I haven't spotted this :-)
• Only the drop makes problems. This means, dragging from palette to canvas shows nothing (wrong) and slows down the system (wrong). When you (blidndly) drop by releasing mous button, after a while the widget appears on the canvas. Then it can be moved on canvas without problems. The slowdown is likely that event queue gets full. The cause is not yet known (I need to debug it on Windows)

[Patrik Svestka]

I made a short screen case to show the issue, so you can see it. Now I found out that it actually shows the widget every time if I don't drag it too far. (the video is packed so it fits here)

[Jan Vrany]

Thanks - this looks similar to what I'm experiencing. After a quick look it looks that the the problem is that gets too busy and slow - the CPU just burns. A huge amount of time is spent in LargetInteger arightmetics as OS time is kept in LargetIntegers internally. Under Win64 LargeIntegers is known to be slow and even buggy (known, outstanding bug).

A quick test proved that avoiding a LargeInteger arithmetics in Win32OperatingSystem>>getOSTime (which is poorly code with that respect) significantly improves the situation but still, far from being acceptable. More has to be done (and Win32OS fix has to be thought through - this might be tricky to get 100% correct).

This is more tricky that I thought initially.

[Jan Vrany]

Maybe fix attempt 1 :-)

[Jan Vrany]

Ah...now I recalled a similar bug I fixed for X11. If I apply the same fix for Win32, the issue goes away.

Could you please try this "fix" and confirm if it helps?

[Jan Vrany]

After a closer look, I found the real cause - I believe - of the problem. My previous fix for the same problem under X11 (ce64e30ecf54/stx.libview) actually cured symptoms, not the disease itself! Reverted in cea144a15948/stx.libview.

A proper (I believe now) fix comes in 83b501bbf3b0/stx.libview and should be in build 2106 and later. Please confirm and - if it works - close the issue :-)

[Patrik Svestka]

Yes, this solves the issue tested on build 2107 :).

Now it works perfectly, you can close the issue.