In dolphin, right-clicking a file name and choosing rename would highlight the part of the filename before the dot and keeps the extension intact. However, if the filename is Arabic with some diacritics, each diacritic would cause part of the extension to be highlighted. e.g. If the filename is: اِسْمُهُ.mp3 and you try to rename it, the whole name would be highlighted including the extension.
Thanks for the report. It seems we are missing RTL support in KStandardItemListWidget::editedRoleChanged().
Can you please confirm this still occurs in a recent version of Dolphin.
I retested with dolphin 20.08.1 and the bug is still there.
Thanks for the info!