Usage:
Use a Windows Tablet with Chrome.
I use ASUS VivoTab Note 8 with Chrome Version 56.0.2924.87 on Windows 10 Home.
Use touch events only(use fingers instead of stylus).
Step 1) Open select and select a value (i found the third one 'lucky')
Step 2) Draw a line into the signature field
Step 3) repeat step 1. At some point you will notice an additional fake click in the upper left of your browser(right around the jsfiddle menu). If you are lucky, you can select an item from the jsfiddle menu just by clicking into the select.
Step 4) It's possible you have to restart your browser to reset the bug. It seems it survives new "Runs" from jsfiddle.