STR:
Set NPP interface to RTL.
Run Find in Files.

Result:
The Progress window is displayed in LTR layout.

Should be replaced with

WS_EX_APPWINDOW | WS_EX_TOOLWINDOW | WS_EX_OVERLAPPEDWINDOW | (pNativeSpeaker->isRTL() ? WS_EX_LAYOUTRTL : 0),

Notepad++ 8.5.1.