Scenario 1:
The mouse cursor is not displayed on the first launch VDA session. clicking can make the cursor display.
Scenario 2:
VDA session is in full-screen mode on the secondary monitor of the dual monitor. Move the cursor from the primary monitor to the secondary monitor, and then the cursor will disappear until there is a click.
Scenario 3:
The mouse cursor randomly disappears during normal use, click can make the cursor display again.
[Solution 1]
Path: HKEY_LOCAL_MACHINE\SOFTWARE\(WOW6432Node)\Citrix\ICA Client\CCM
Value: AllowMouseEvent
Type: REG_DWORD
Data: 0x1
Note:
1. The "CCM" key should be manually created under HKEY_LOCAL_MACHINE\SOFTWARE\(WOW6432Node)\Citrix\ICA Client\
2. Restart the Workspace app for Windows to make the registry take effect
[Solution 2]
The issue appears that the Desktop Viewer window somehow didn't get focused after launch.
The mouse pointer didn't show up inside the window until an explicit mouse click to make the window re-focused.