Is that a webkit rendering issue in Safari 5.1?

Question

I add my voice to rendering issues encountered in Safari 5.1, here they are:
1) Fonts look pixelated on some websites. Here's an example drawn from weebly.
The font used here is OFL Sorts Mill Goudy, so I guess there must be a font rendering engine in weebly that allows non web safe fonts to be displayed properly. That works fine in Firefox 5 & 6, and until recently on Safari 5. Chrome 12 has exactly the same issue as Safari 5.1, so it could be a general rendering issue in webkit.
2) Videos on Vimeo show now a black rectangle instead of the video.
3) The "Insert image" feature in this forum takes forever to load, displaying a white rectangle during several seconds. Same issue with the Evernote clip bookmarklet.
Hope these issues will be fixed soon, any help is appreciated if something can be changed in Safari settings.
Note: resetting Safari (including cleaning cache) doesn't solve the described problems. I'm running Snow Leopard 10.6.8 on Mac Pro Quad 2.8 Ghz.

Answer 1

Thanks for helping diagnose this.
However, my testing indicates that this is not a bug with border-collapse: collapse. Here is why:
If I change the value of border-collapse to "separate" and add "border-spacing: 0", the bug remains. To try this, request http://www.panlex.org/cgi-bin/plxu28-bug2.cgi .
If I leave the value of border-collapse unchanged but change the button elements in the cells to plain text, the bug disappears. To try this, request http://www.panlex.org/cgi-bin/plxu28-bug1.cgi .
On the basis of this testing, it would seem to me that the bug is dependent on the button elements and independent of the border-collapse CSS attribute.
This doesn't explain, however, why you have found border-collapse: collapse producing slow results with other large tables and it doesn't do so with my table in http://www.panlex.org/cgi-bin/plxu28-bug1.cgi . It also doesn't explain why you saw the bug disappear when you changed border-collapse on my page but I didn't see it disappear.
Any further diagnostic help would be welcome.