The empty space in split FileSystemDock doesn't register as current folder for drop operations

[mieldepoche]

Tested versions

it has always been the case,
still in v4.3 dev 5

System information

linux

Issue description

dropping a node branch	dropping a resource from the inspector
simplescreenrecorder-2024-03-30_16.37.31.mp4	simplescreenrecorder-2024-03-30_16.41.36.mp4

I expect the target folder to be the current one when dropping in the empty region.

Steps to reproduce

• split your FileSystemDock and create folders
• drag a node from a scene to the dock and notice the wrong target path

Minimal reproduction project (MRP)

any