Add WS_EX_TOOLWINDOW window style (#17711)

Fixed: #17696

Summary of the issue:
When the highlighter is enabled, the NVDA Highlighter Window icon is fixed on the taskbar after restarting Explorer.

Description of user facing changes
The NVDA Highlighter Window icon is no longer fixed in the taskbar after restarting Explorer.

Description of development approach
Add a WS_EX_TOOLWINDOW window style to the highlight window.

source/visionEnhancementProviders/NVDAHighlighter.py

@@ -1,7 +1,7 @@
 # A part of NonVisual Desktop Access (NVDA)
 # This file is covered by the GNU General Public License.
 # See the file COPYING for more details.
-# Copyright (C) 2018-2023 NV Access Limited, Babbage B.V., Takuya Nishimoto
+# Copyright (C) 2018-2025 NV Access Limited, Babbage B.V., Takuya Nishimoto, hwf1324
 
 """Default highlighter based on GDI Plus."""
 
@@ -83,6 +83,9 @@ class HighlightWindow(CustomWindow):
 		# Make this a transparent window,
 		# primarily for accessibility APIs to ignore this window when getting a window from a screen point
 		| winUser.WS_EX_TRANSPARENT
+		# Ensure that the window is treated as a tool window,
+		# so that it will not be shown in the task bar
+		| winUser.WS_EX_TOOLWINDOW
 	)
 	transparentColor = 0  # Black
 

user_docs/en/changes.md

@@ -118,6 +118,7 @@ In any document, if the cursor is on the last line, it will be moved to the end
 * In Visual Studio Code, NVDA no longer hijacks the `alt+upArrow` and `alt+downArrow` gestures for sentence navigation. (#17082, @LeonarddeR)
 * When anchor links point to the same object as the virtual caret is placed, NVDA no longer fails to scroll to the link destination. (#17669, @nvdaes)
 * Voice parameters, such as rate and volume, will no longer be reset to default when using the synth settings ring to change between voices in the SAPI5 and SAPI4 synthesizer. (#17693, #2320, @gexgd0419)
+* The NVDA Highlighter Window icon is no longer fixed in the taskbar after restarting Explorer. (#17696, @hwf1324)
 
 ### Changes for Developers