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I am confused about how "Marked All Viewed" is working. I have some server up tests running once a minute, the menu bar icon has a Yellow circle, I click "Mark All Viewed" and it goes away. One minute later it is yellow again. Seems to me it should only change when a test fails or changes. I don't want to have to click once a minute to clear the status, seems silly.
Re: Mark All Viewed
The Mark All Viewed clears the yellow circle and yellow dots in the Monitor window, as you found. Those markers appear when a test has changed — they are change markers.
If you don't care about changes, you could simply ignore the markers, or disable them via the "Include unviewed indicator on Dock icon and status menu" General Preference and/or hide the column in the Monitor window.
(You could also disable the Smart Change Detection option in your tests, if you don't want to detect changes.)