UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.146 Safari/537.36

Steps to reproduce the problem:
1. Open multiple browser windows
2. In the plasmashell button for Chrome, select a window
3. Sometimes plasmashell freezes (a couple of times per day, or immediately after restarting 

What is the expected behavior?

What went wrong?
I see lots of:

QXcbConnection: XCB error: 2 (BadValue), sequence: 13975, resource id: 56624860, major code: 142 (Unknown), minor code: 3
QXcbConnection: XCB error: 2 (BadValue), sequence: 13976, resource id: 56624860, major code: 142 (Unknown), minor code: 3
QXcbConnection: XCB error: 2 (BadValue), sequence: 13977, resource id: 56624860, major code: 142 (Unknown), minor code: 3
QXcbConnection: XCB error: 2 (BadValue), sequence: 13978, resource id: 56624860, major code: 142 (Unknown), minor code: 3
QXcbConnection: XCB error: 2 (BadValue), sequence: 13983, resource id: 56624888, major code: 142 (Unknown), minor code: 3

as I scroll up and down through Chrome's windows, until it freezes and I have to restart plasmashell

Did this work before? Yes 

Chrome version: 65.0.3325.146  Channel: n/a
OS Version: KDE neon LTS 5.12
Flash Version: 

Not sure whether this is due to kde neon updates or Chrome updates, since both happened at the same time, but it is new behaviour (ie last week or 2).