Wacom Tap to Left Click Doesn't Work with Drop Down Menus

While using a Wacom tablet, if you tap to click on drop down menus they will not open up. The menu will appear for a moment then close immediately. Occasionally if you click away from the drop down then select the drop down again it will open.

Found in 4.20  CL# 4369336, 4.21 CL# 4541578, 4.22 CL# 4589258

1. Connect Wacom Tablet 
2. Open the Editor
3. Tap to click on any drop down menu

Results:
The menu will appear for a moment then close immediately.

Expected:
The menu would open

ランドスケープで地形やキャラクタが黒くなります。