adding new folders in the file manager with "save and new"-button

[virtucol]

Wouldn't it be nice being able to set up a series of new folders (within the same previously selected destination directory) by having a submit button "SAVE and NEW" (besides the "save" and "save and close" buttons), in the same way as it is possible adding new pages in the page structure...!?

At the moment, to do this, I have to repeat the process of selecting "new folder", selecting the destination and hitting "save and close" for every single folder I want to set up in the same directory.

[Serhii-DV]

also, other similar file manager improvements: #2907, #2168