Bug: jumping stack windows (when supress messages is off)

David Bovill david.bovill at gmail.com
Fri Oct 9 09:00:46 EDT 2020

Windows intermittently jump to a location on the screen when I move windows. It’s got too annoying to ignore.

• Is anyone else having this problem?

I am testing this on Mojave and Livecode 9.6.1 rc2. I am testing this without any of my own code such just was IDE stacks. This I “think” is quite a long standing bug that I suspect is related to the global coordinate system as I have been working around this for quite a while now.

The location of the jump seems to be the same horizontal x location. But with the vertical value being reset to the halfway point.

I am testing by. Simply moving the message box. It is intermittent - so occurring about once every 5 moves, and strangely is happening only when the top left of the stack window is within the top left quadrant of the screen. Using. The following code int eh message box I find the top of the message box stack is always 492 after a jump (see below). This appears to be related to half the screen less the decorations like menu?
	put the screenrect & CR & the rect of stack” Message box"


As a further indication that the problem is due to the IDE, I find that creating a test stack (no scripts or controls) exhibits the same behaviour - but this behaviour can be suppressed by choosing “Suppress Messages” from the “Development” menu. This suppression has no effect on the message box or other IDE windows which still jump intermittently.

The problem is most intense when working with multiple screens. For at least a couple of years stacks I create and place on second or third monitors receive mouse clicks in the wrong location. This happens on different machines, and different. Monitor setups. Only tested on Macs.

I am currently creating a multiscreen app - so taking the tracking down. Of this bug more seriously. The current tests are one on my laptop without external monitors, and having restarted the computer (several times). Applications other than Livecode don’t suffer this problem.

How should I report this bug - should I submit a video / screen recording?

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