But Opera still has a fairly small share of the browser market, and developers often don't think about Opera users. Usually that's not such a big deal, as Opera supports all the major web standards. But certain online applications like Google Docs & Spreadsheets, Google Calendar, and Picasa Web don't play very well with Opera.

Back in January João Eiras developed a patch that fixed some known issues with those programs.

• Fixed mouse scrolling in Google Spreadsheets so that when you roll the scrollwheel down, the page moves down.
• Remove the "browser not compatible" notice in Google Calendar, and allow event popups to work
• Remove the "browser not compatible" notice in Picasa Web -- the program works fine on Opera, and the warning just doesn't make any sense.

Well, apparently when Google went and updated some of their services, many of these patches stopped working. Eiras has updated his script a few times, but he says several issues have popped up with Google Spreadsheets.
[via Opera Watch]