App designer stuck every 2 runs

I recently started working with App Designer and am overal quite happy with it. However for some reason matlab gets stuck while running (but while not actually starting the script).

What happens is that I simply press the Run button, which then greys out, and then nothing happens. Matlab also doesn't respond to other input anymore for a few minutes, like saving the program or closing it. However, when I'm lucky it will respond to saving/closing after a few minutes (but the run button will still be greyed out). When I'm not lucky I need to kill matlab.

As this frequently happens on the second/third time I run my script, this is becoming quite frustrating.

Is this a known issue? Is there anything I can do to fix it?

Maybe related might be that sometimes debugging does not work properly. Occasionally it will stop the program on a certain line, but there will be no debug menu (no "quit debugging" or "continue", but I CAN "run" the program again, which will then crash though).

Some details:

Matlab version: R2019b (Ubuntu 19.04 & 19.10)

My app contains: Axes, various dropdown boxes, a button, listbox, some labels and a slider. Data in the axes is refreshed when the user interacts with certain dropdownboxes and the slider.

My startupFcn sets some paths (not matlab paths, just fill string variables using dir() ) and two app.variables based on the value of a dropdownbox and slider.

Steps to reproduce:

1. Start matlab
2. Home -> new -> App
3. Open "Respond to User Selections" Example (PatientsDisplay.mlapp)
4. Run
5. Click around a bit (Hospital name, Gender, Smoker, Plotting options, Blood Pressure)
6. Close (by pressing the X in the title bar)

Repeat steps 4-6 a few times (it starts hanging after ~6 runs in this case, maybe because the example app is a lot smaller than my own)

[Hari Krishna Ravuri]

Please provide reproduction steps

[Alberto Urban]

Hi, I have the same problem.

Have you found a solution to the problem?

[Markus de Ruijter]

I haven't found a solution yet unfortunately.

However I did notice that you do not always need to exit and re-run the application after you change something. For example, if you made a change in a ButtonPushed method, the new code wil automatically be run the next time you push that button (without restarting the application).

So this reduces the number of time you need to restart the application, and makes this problem slightly less of an issue.

[Stephen Scripp]

Same issue. Runs great first time around and then crashes second time.

[daniel mitchell]

If you can download the newest MATLAB version it may help (it helped me with similar problem in the app designer)