Description of the Issue

The issue is reproducible for any folder picker dialog that allows a user-specified initial file path via [...] button.
Can be found in:

• Preferences > Default Directory
• Preferences > Backup > Custom Backup Directory
• Preferences > Cloud & Link
• Search > Find in Files
• etc

Steps to Reproduce the Issue

1. Menu: Search > Find in Files
2. Specify a non-existent file path in Directory: edit box (or leave completely blank)
3. Press the [...] button
   

Expected Behavior

Select a folder... dialog is shown

Actual Behavior

No new dialog is shown.

Debug Information

Notepad++ v7.9.3 (64-bit)
Build time : Feb 22 2021 - 22:47:45
Path : E:\Development\notepad-plus-plus\PowerEditor\visual.net\x64\Unicode Debug\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 2009
OS Build : 19042.804
Current ANSI codepage : 1252
Plugins : none