Created attachment 249050 [details] test case Open the attached test case. Click on the button 'Red' and then click on the button 'Lime'. Result: The area of the lime rectangle is only repainted and since the lime rectangle is smaller than the red rectangle, the bottom of the red rectangle is not cleared. Expected: Changing the source of an iframe to an SVG with no intrinsic size should repaint its old rectangle. Note: The dirt is cleared is the window is refreshed (resized for example).
<rdar://problem/20228302>
The bug is not reproducible if the css "float" property is set to "none".
This bug still exist in WebKit ToT (268117@main) while Chrome Canary 119 and Firefox Nightly 119 do not exhibit this issue.