This is something I encountered about when switching to Linux recently (Manjaro specifically). Dragging & dropping only works on startup for the first files, however subsequent files are completely disregarded. Reopening closed tabs also often opens the reopens wrong file. I’ve tried the Steam version and both release and beta versions, none of which have cooperated. This is really frustrating, as I was hoping to ditch Windows entirely.
Versions: Aseprite 1.3-rc1, Aseprite 1.2.40
Operating System: Manjaro Linux
KDE Plasma Version: 5.26.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.12-1-MANJARO (64-bit)
Graphics Platform: X11
Processors: 4 × AMD A8-7600 Radeon R7, 10 Compute Cores 4C+6G
Memory: 6.7 GiB of RAM
Graphics Processor: VERDE