Thank you!
Calling ReInit on Resume makes the controls visible again
At the same time, the problem is not completely resolved, the behaviour of some controls is a little changed...
For example, if I have a jMediaPlayer which is playing something, if I call ReInit() on the Resume event, the app will crash. Anyway now I will study what happens inside of ReInit and maybe if I understand better what is going on, I can solve the problem in a better way.
Can I ask you one more favour, jmpessoa? Actually, two favours...
1. Can you tell me what are the versions of Java, JDK, NDK, Lazarus, and FPC that you are using? I will try to reinstall everything using the exact same versions that you are using, and maybe things will work better.
2. You said you cannot reproduce the bug. In that case, can you please build one of your demo project (for example, AppCompatCollapsingToolbars1, and then zip the whole folder of the project, including the APK, and upload it somewhere so I can get it? In this way I can compare a compiled version that works with my version (that doesn't work without ReInit) -- I will compare manifest files, java files, APK files, etc. and hopefully I will learn something useful to solve this problem at the root. And of course I'll share here everything I learn that might be useful to others.
In any case thank you very much for the kind help and for developing LAMW!
M.M.