Bug 21722 – REGRESSION: Graphical corruption when scrolling with middle mouse button

• Component: Layout and Rendering
• Status: RESOLVED CONFIGURATION CHANGED

[Robert Xiao]

Scrolling using the middle mouse button causes chunks of the page to be replicated at the wrong places. The wrong pieces are deposited near the pointer.

Steps to reproduce:
1) Go to any webpage that can be scrolled (horizontally, vertically or both)
2) Push the middle mouse button to invoke scrolling mode
3) Move the mouse to scroll in any direction

Result: chunks of the page are improperly duplicated, resulting in what appears to be graphical corruption

Expected result: page renders properly as it is scrolled

This was tested on WebKit r37604 (nightly, Oct 15 2008).

[Robert Xiao]

Created attachment 24473 [details]
Screenshot of bug after scrolling slowly

Scrolling slowly up and down (by moving the mouse up and down after invoking scroll mode with the middle mouse button) results in this mess near the cursor.

[Robert Xiao]

Created attachment 24474 [details]
Screenshot of bug after scrolling quickly

Scrolling rapidly up and down (by moving the mouse up and down after invoking scroll mode with the middle mouse button) results in large parts of the page becoming incoherent.

[Dave Hyatt]

Probably broken by my ScrollView refactoring.

[Robert Xiao]

Still broken in the latest WebKit nightly (r39293). Is no

[Robert Xiao]

I have no idea where "Is no" came from, but it was unintentional.

[Ahmad Saleem]

We don't have reduction and it was regression in 2008 and now a days, wikipedia works pretty much fine and does not have text wrapping issues, which are highlighted.

I think we can safely close this as 'RESOLVED CONFIGURATION CHANGED'.

Doing so, please reopen, if it needs to be tracked. CCing Alan and Simon for any insight.