scroll horizontalScrollbar get an error in Firefox

[lasiaz]

Expected Behavior

no error

Actual Behavior

event is not defined

Steps to Reproduce

scroll the horizontalScrollbar

Operating System and Browser

Windows 10, Firefox 64

[BryceLTaylor]

Yes, I can reproduce this.

In order to see the error you need to scroll by clicking and dragging the scrollbar at the bottom of the paint editor. You can not see the error by two finger scrolling with a track pad.

The error doesn't prevent scrolling or seem to have any affect on the paint editor

[BryceLTaylor]

Steps to Reproduce

Open a new project in firefox (Windows or Mac)
Open the console
Open the paint editor
Scroll horizontally with two fingers on a track pad
Note: no errors appear in the console
Click and drag the vertical scrollbar
Note: no errors appear in the console
Click and drag the horizontal scrollbar
Note: an error appears in the console

I'm seeing this error in Firefox on windows and mac, but not in chrome or safari.