2020B causing panels to vanish in App Designer, potential bug?

I have an app designer project which was first created in 2019a.

It has been moved into 2019b and later on to 2020a without issues.

Now, when I open the 2020a version in 2020b, it gives me the standard message saying it succesfully converted it to 2020b.

Above is what it looks like after opening, the automatic convertion, and saving the document.

If I now reopen it, the tab group in "IMAGE PARAMETERS" and the three images in the images tab group disappear.

They haven't just moved somewhere, they have vanished from the component browser too.

I am honestly a bit perplexed as to what could be causing this, if not a bug.

I have tried moving the sections away from their location before saving, or renaming the components but no such luck.

It seems it may be related to bug 2066232: Placing a table UI component in a grid layout manager causes App Designer .mlapp file corruption.

As the three images are snapped to a grid layout, and the tab group in "IMAGE PARAMETERS" also uses grid layouts within each tab.

Strangely though, most of the panels/tab groups/etc. use grid layouts, and only the two mentioned previously are affected.

Does anybody have any suggested workarounds, besides the obvious downgrading to 2020a?

Thanks!

[Mario Malic]

I do not know how the process goes when updating between versions. You open the app, it converts, saves and closes the app?

This might be a silly guess but worth a try. TabGroup is clipped a little bit on the right side, try to reduce its size so it fits the Panel before conversion. Also, try playing with the Parent property of the TabGroup, maybe set it to main window and see if it still remains after conversion.

[Scott]

When the app is opened for the first time in a new version, it automatically converts it to the current version. I manually save/close the app afterwards.

I have tried some variations of what you suggested, and changing the parent property seems to be a workaround.

As soon as the parent property for either of these elements is a grid layout while saving, they will vanish on the next launch.

So, I can work around this by just inserting them into these locations without a grid layout.

Strangely enough, for this to work I had to move the components out of their grid layout, attach them to a different panel, save, re-open, remove the grid layout they were attached to beforehand, and then I can move them back into their original locations. If I did all of this in one step, they would still vanish.

The downside is that they are now not in a grid layout, so they don't resize as nicely, but oh well.

[Mario Malic]

You can try making a test app with simple Panel with Grid Layout and a Tab Group and check if conversion is related to your specific settings or it's a bug.

Also, from your first picture, the Check Box at Projects panel and Ymax are missing. If they are in grid layout as well, shouldn't all of them be missing?

[Scott]

You are right, I hadn't even noticed they were missing yet, thank you!

That's the part that confuses me, pretty much all of it is in grid layouts, yet only select elements are vanishing, and I cannot find a single common thread between the vanishing components.

[Mario Malic]

Well, I would compare properties of components that remain and are gone after conversion, maybe there's something going on there. However, Parent/Child properties should be correct, since it's not possible place a component outside of grid layout.

[Ruger28]

I had a similar issue going from 2019a to 2018b. My image panels disappeared. Turns out, 2018b does not contain the ability put images in the app. So, everytime someone would open my app using an older MATLAB, it would remove them, and they are gone forever (until I remade them, multiple times).

Maybe it is something that 2020b does not support anymore?

[Scott]

I don't think that's the case here. The release notes don't mention any removals of such that would affect me. There are some noted changes to GridLayout, but the release notes say only the background colour of the gridlayout is no longer transparent. I could see this causing items to be hid behind others, but then they would still remain in the component browser, which they unfortunately don't.

[Marco Frieslaar]

I am seeing similar problems in 2021a.

My graphs and images keep being deleted and I have to painstakingly put them back in all their detail. But I have also experienced a problem where it won't let me drag and drop a UIAxes back in again.

Also, when I make changes to a component in 'Inspector', there is a long delay before the change materialises on the component and sometimes it doesn't work at all - or, it will be mysteriously deleted a while later.

This version is not good for 'appdesigner' and is just creating more work and so I have gone back to struggling with the previous release. 2021a is a disappointing effort from my viewpoint. I haven't got time for all this faffing about with bugs and major MATLAB foibles.

Answer 1

[Cris LaPierre]

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