I'll refer to "GDX Texture Packer GUI" as "GTPG"

Some days ago I got a strange glitch in my GDX Texture Packer GUI.

Every time I'd open the jar (or any other GTPG executable), nothing would show on screen, but it would show on the task bar and the task manager that the app was open.

When I tried to open it by the command line (java -jar) I got a warning that read something like this (I don't have the exact words anymore).

LibGDX 1.9.3 recommended to Vis UI version XXX, you're using LibGDX 1.9.2
Some things might not work

So I to got the source code to change the GDX version, but it was already up-to-date and the GTPG was still not working.

Finally, I gave up on the glitch and just downloaded an older version to see if it worked, and it worked just fine. So fine indeed that the newer version returned to work out of nowhere.

Don't know how the glitch was caused, don't know exactly what fixed it.
The only clue I have to the cause of the bug is that I might have turned off my computer without closing the app. Other than that, nothing comes to my mind.

Thought I already solved it, I was recommended to post this anyway so other people would know what to do

• TL;DR App was open but hidden, open old version and it's fixed