[WIN32SS?] Opera 9.64 fast scrolling in alterning direction text-drawing-dirt may remain

Reproduction steps

• install Opera 9.64 from rapps
• open its "about" function (menubar help->about)
• scroll fast with the mouse wheel through the page in alternating directions

Expected result
The text should always be displayed correctly

Observed result
Sometimes, most likely after having changed the direction of scrolling, the text is not redrawn correctly, but instead fragments from the past seem to remain
0.4.13-RC-41-gc6b2f3a_affected.webm
0.4.13-RC-41-gc6b2f3a_affected.log (ros logs nothing when doing this)