Initially, downloading Krita-5.1.21 failed to launch. After downloading Krita-6 and Change the content of the exec file in the desktop icon file, clicking the application icon caused Crystal Dock to disappear.
First:
ubuntu@master:/usr/share/applications$ cat krita.desktop [Desktop Entry] Type=Application Name=Krita 5 Exec=/opt/tools/krita-5.1.21-x86_64.AppImage
Change the content of the exec file in the desktop icon file:
ubuntu@master:/usr/share/applications$ cat krita.desktop
[Desktop Entry]
Type=Application
Name=Krita 6
Exec=/opt/tools/krita-6.1.0-x86_64.AppImage
second:
Click krita icon

Crystal Docker will disappear.