I almost exclusively use SourceTree with the uncommitted changes filter mode set to 'modified' (among other reasons, primary one is I am way too lazy to maintain .gitignore)
Anyways, selecting this mode is the very first thing that I do for each and every repository that I open under SourceTree; on top of that, as I recently found out my mac was very often running low on memory, I tend to close sourcetree projects easily, which makes all the more tedious to have to click that 'modified' box each time
So I guess you can see where I'm headed: is there a way to set up SourceTree so that it will use this 'modified' policy by default - IIRC this was the case on very early releases of the tool, which somehow remembered the setting across sessions.
There isn't a way to 'force' it to do so. We need to build such functionality into the app and there are technical challenges around doing currently. You can vote on this ticket and watch it for future updates.
Senior Mac Developer, Sourcetree