2. add an option to NOT remove folders with diff tpl
It is a preferable solution of the first one
3. never remove folders with diff tpl
This last solution of my preference, by adding it however a supplementary condition: when a file is added, if one of the options by default is modified (diff tpl, access rights, hide, browsable,changing the default name,...) then the file cannot be destroy automatically.
On the other hand it is necessary to have an option (activated by default)
for the user to authorize or not the destruction systematics of the empty folders.
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One more would be an option in the VFS popup allowing to make a reset of the options for the selected files:
Reset default options for this folder