It will "work", it will just be "slow". If you set EXTEND_PAD, then all images will be scaled in software, which will require a read from the x server and a write back for /every/ image paint. If you don't set EXTEND_PAD, then testcases such as https://bugzilla.mozilla.org/attachment.cgi?id=209616 and see that it doesn't work will fail.
It will "work", it will just be "slow". If you set EXTEND_PAD, then all images will be scaled in software, which will require a read from the x server and a write back for /every/ image paint. If you don't set EXTEND_PAD, then testcases such as https:/ /bugzilla. mozilla. org/attachment. cgi?id= 209616 and see that it doesn't work will fail.