Hello,
I know this thread is old, but this is how it worked for me.
First, you have to make sure that drag is checked in boot camp control panel.
The Drag works in the following way:
- if you choose to make the secondary click on the left corner, then you can only drag with the bottom right corner of your trackpad.
- if you choose to make the secondary click on the right corner, then you can only drag with the bottom left corner of your trackpad.
In other word you can only drag with a specific region of your trackpad, which is kind of odd with you use to drag with the entire trackpad.
I hope this help
Cordially