UserAgent: Mozilla/5.0 (X11; CrOS x86_64 11151.17.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.27 Safari/537.36
Platform: 11151.17.0 (Official Build) beta-channel coral-unibuild (astronaut babymega babytiger blacktip blacktip360 blacktiplte blue bruce coral epaulette lava nasher nasher360 porbeagle rabbid robo robo360 santa whitetip)

Steps to reproduce the problem:
1. Open PCManFM (linux application)
2. grab bottom right corner
3. drag corner to right

What is the expected behavior?
Normally, the cursor should stay on top of the corner as you drag it.  In this case, the cursor moves farther than the corner.

What went wrong?
Here's what I think is a key to finding the answer.  If you hover over the lower right corner, you can make two different cursors appear.  When you are slightly up from the very bottom and to the left of the right edge, you get the L or angle shaped icon.  This is the icon that is present when the expansion doesn't work properly.  Grab and drag and the icon moves farther than the corner of the window.
If you hover over the corner slightly lower and more to the rightmost edge, you get the double headed arrow corner icon.  When dragging with this icon, the cursor and the corner move together.
Usually once you've grabbed the corner with the angle shaped icon once, it will no longer work to drag the corner a second time,  The double headed arrow icon will still work properly.

Did this work before? N/A 

Chrome version: 71.0.3578.27  Channel: beta
OS Version: 11151.17.0
Flash Version: 31.0.0.135