In the Console section of the Web Inspector, there are filters for these log levels: All, Errors, Warnings, and Logs. You can select individual filters, or via cmd-clicking you can select multiple options. However, reloading the page causes the inspector to lose this selection setting it back to All. This is an annoying quirk because as I develop pages and debug issues I'll often reload numerous times to test out my latest changes. If I’ve made a change to the selected log level there’s a reason: I don’t want to see those levels.
If this behavior I’m reporting is less a bug and more an intentional feature I’d like to recommend having ⌘R be a trigger for reload-and-preserve-log-level. My intention here is “let me try again” or “let me try my new code”. Filtering my log levels is a common step in debugging to show me only the most relevant information. This would still allow Safari to reset the log level when going to a new page (which seems like a good thing to do - just because I was debugging one page doesn't mean I don't want to be alerted to errors on a new page).
This is a bug. Patch to come shortly.
Created attachment 247761 [details]
Committed r180935: <http://trac.webkit.org/changeset/180935>