Created attachment 147757 [details]
video

SUMMARY
[I recorded a git so you can see what happend.]

I have a file with multi-line filename. in folder model, when I drag it for the first time, nothing happens
the selection is a rectangle whose height longer than width because of the multi-line filename.

But if I drag it for the second time, the selection changes to a square,  so the font in the filename is flattened.
the selection will remain square shape no matter how many time you drag the file then.

Until you drag another file with one-line filename. then drag the multi-line file, the selection changes to rectangle again.

STEPS TO REPRODUCE
1.  change to folder model. create two files, one has one-line filename, another has multi-line filename.
2. drag the multi-line filename file twice. for the first time, the selection is rectangle; for the second time, the selection changes to a square. no matter how many times you drag the multi-line filename file, the square selection remains
3. now drag the one-line filename file once.
4. drag the multi-line filename file, the rectangle selection comes back.
5. drag the multi-line filename file again, the rectangle disappears and the square selection turns out again.

EXPECTED RESULT
the selection is always rectangle shape for the multi-line filename file.

SOFTWARE/OS VERSIONS 
Linux/KDE Plasma:  openSUSE Tumbleweed, Plasma 5.24.3
KDE Plasma Version: Plasma 5.24.3
KDE Frameworks Version:  5.92.0
Qt Version: 5.15.2