The left-edge behavior has another issue, but it turns out not to be related to this fix.
Swiping from the left edge will cause the current scope to be switched to "Today" as soon as the first commit point is reached, even if the user only swiped far enough to bring up the quick launcher. This action isn't reversible; swiping back the other way does not return it to the scope they were using. It makes much more sense to me to only switch back to the default scope if the user explicitly presses the Ubuntu icon in the launcher.
The left-edge behavior has another issue, but it turns out not to be related to this fix.
Swiping from the left edge will cause the current scope to be switched to "Today" as soon as the first commit point is reached, even if the user only swiped far enough to bring up the quick launcher. This action isn't reversible; swiping back the other way does not return it to the scope they were using. It makes much more sense to me to only switch back to the default scope if the user explicitly presses the Ubuntu icon in the launcher.