Synchronize create zero file size (and more)

[mmm4m5m]

I am new MME user. I use it with android only, I did not connect with computer. I use it offline, I did not login, I do not have online profile. I do not know the other use cases for "synchronize".

I have Android 9 Pie and OnePlus 3T device.

New database is created in: "Android/data/com.money.manager.ex/files/databases/test.mmb" And "synchronize" is using the same location.

1. I can create new database, make changes, close application. Open again, add more changes, etc. It works fine. BUT if I click "synchronize" it will result in zero file size and all changes will be lost.

2. I can move the database file and open it: "Android/test.mmb" I can modify and all changes are saved to: "Android/data/com.money.manager.ex/files/databases/*.mmb" This is not obvious. It is confusing! When I click "syncronize" the database is saved to: "Android/test.mmb"

3. If I open databse: "Android/test.mmb" In "settings/database" I see this name: "Android/data/com.money.manager.ex/files/databases/*.mmb" "Syncronize" will use "Android/test.mmb" BUT that file name is not shown anywhere!

Note, I did NOT give storage permissions. Looks like it is not needed. Described actions above - open/save - work without storage permissions. (Edit: My tablet have Android 7.0 and storage permissions enabled for MME. There, in "settings/database" I see "Android/test.mmb". And "syncronize" will update the other file: "Android/data/com.money.manager.ex/files/databases/*.mmb" )

I think something is wrong and review/change/fix is needed: a) file/database create/open screens (initial startup screen and settings/database) b) save/syncrinize actions.

4. I would like to save my database to the application data/settings directory. That is more safe because other applications can not access and read it. Also storage permissions are not needed. I tried. From MME, open database, for "select file" I used "Material File" (from FDroid with root access) and I selected file from: "/data/data/com.money.manager.ex/..." It did not work. Then I changed file names in "com.money.manager.ex.recent_db.xml" and it worked. I would like if application natively support this location for open/save database.

Thanks!