Pat, I use the pen with my tablet, an Intuos 3 4X6 and don't have a Wacom mouse
In the tablet set up there are a couple of things that I thought might be involved
The default function for the upper button on the pen is double click, I have changed it to single click just in case I was pushing it.
There is also an adjustment called "Tip Double Click Distance", I have set it to Off and also to maximum
Alas, no change. Double tapping the pen tip still brings up the aligned tick.
At least now we know the reason rather than presuming that the system is haunted
Just did a quick check of the Wacom site, there is no mention of this and I am trying to sort out their driver update instructions. The manual for my tablet mentions double click speed but so far I cant see if it is adjustable