Notepad++ v8.9.9 vulnerability fixes, new features & bug-fixes:

1. Vulnerability: Fix WM_COPYDATA sender authentication bypass. CVE ID not assigned yet
2. Vulnerability: Fix WM_COPYDATA privilege escalation allowing launch plugin commands execution. CVE ID not assigned yet
3. Vulnerability: Fix heap disclosure. CVE ID not assigned yet
4. Vulnerability: Fix TOCTOU risk when saving temp file under UAC. CVE ID not assigned yet
5. Vulnerability: Fix out-of-bounds array access via NPPM_MENUCOMMAND. CVE ID not assigned yet
6. Fix heap buffer overflow in SAML decode of MIME Tools plugin. CVE ID not assigned yet
7. Update to Scintilla 5.6.7 & Lexilla 5.5.4. (Implement #18428)
8. Improve Find in Files performance. (Fix #15248, #13730)
9. Add an option to change dialog font & font size. (Fix #5648, #9914, #10745, #17183)
10. Add an option to display the Incremental Search bar at the top. (Fix #18486)
11. Remember incremental Search options across sessions. (Fix #18484)
12. Enhance the Cliboard history panel UI. (Implement #18531, #18559)
13. Fix files not opening via “Edit with Notepad++” when app path use 8.3 path format. (Fix #18530, report)
14. Fix Document Switcher persistence issues. (Fix #10574, #10950)
15. Fix loss of editor focus when dismissing the Document Switcher with Ctrl+Esc. (report)
16. Fix Clipboard History buffer over-read & truncation of UTF-16 surrogate pairs. (Fix #18519, #report)
17. Fix the current doc hidden due to missing auto-scroll in Windows dialog listview. (Fix report)
18. Fix incomplete repainting of Windows dialog list after resizing then sorting. (Fix #16267)
19. Fix the ESC key not closing Windows dialog after a document is closed. (Fix #18554)
20. Add UDL as a selectable default language for new documents. (Fix #979, #11097, #18325)
21. Detect external file modifications in both views instead of only the active view. (Fix #7581)
22. Add Structured Text language support. (Fix #18365)
23. Fix several memory leaks. (Fixed by #18466, #18467, #18465, #18473, #18482, #18512, #18535)
24. Fix Markdown UDL link highlighting being broken by ‘@’ in the URL. (Fix #18009)
25. Fix Find-in-Files macro playback ignoring empty filters. (Fix #8170)
26. Fix Count and Mark All ignoring zero-length regex matches. (Fix #7896)
27. Fix bugs in Function List for C, TypeScript, INI and PowerShell. (Fix #10162, #18358, #18574)
28. Fix the “inherit” flag for FG/BG not being cleared in Style Configurator. (Fix #14197)
29. Set new UDL to use theme FG, transparent BG, no bold/italic/underline by default. (Fix #18387, #5622, #17054)
30. Fix spurious NPPN_READONLYCHANGED notification when files are deleted. (Fix #16289)
31. Fix call-tip parameter highlighting being confused by commas in string literals. (Fix #8650)
32. Fix missing warning display when deleting files from Notepad++ on Windows 7. (Fix report)
33. Update Python & R keyword lists. (Fix #18464, #18445)

TODO: Provide the issue links.

The new release will be available in about 7 days.