problems to save on mac - Catalina 10.15.7

I just installed the dmg for mac.
Its the first time i use the software. I made a drawing and saved it.
then i exit the program and tried to open it directly and the drawings was not there.
I opened the application and tried to open it from the application. the files opened... empty.

I made another drawing. I saved it. I closed it. I opened it again and the drawing was there.
However, once i close the application and I try to open the drawing agian, it is gone...

any hints on what is happening?


thanks

meiro

just an update:
I learnt that if I double click on the file to open the app i get an empty drawings, but, if I open first the application and then from inside the application I open the file, the drawing is there.
so the problem is about how the application manages opening with a file after o starting...