Bug with 2 monitor...Block exceed the scree, and I can't reduce the size of it.

Hi guys, I have used fence since last year. And this bug trouble me since then.....

Every time i plug in an extra monitor, the size the block goes strange.  Sometimes the bolck even far exceed the screen....So I can't reduce its size, and can't delete the block either! And now I can't even see my icons in the block...I guess the vertical size already boomed to size around (*50 icons)

For more information, my laptop's resolution is 2560*1440. And my extra monitor is 1980*1080. Maybe it's the resolution of two monitor not match that cause the bug?

Somebody who can help me fix this problem? With Big thanks!