When I reset the View Size from 840 x 588 (too small for me to read) to 1200 x 840, then hit Default ( I assume this sets the Size to my selection), well it doesn’t. Still returns to the smaller size when I exit and return.
Version 2.0.6 in Current Reaper
Win 10
I’m having he same issue in Ableton 
I’m seeing this too (Windows 10 with REAPER and SAVIHost).
Well this didn’t get fixed in V2.0.7, Can we hope to see it in next iteration? Can’t tell you how annoying this is. BTW the " slightly" larger font size option is much appreciated.
Wait, I just noticed that the GUI can be sized on the screen with a pull tab on the bottom right. When I do this, picking a nice size, the preferences calls this “custom” and now this can be set to default. OK, why didn’t some one just tell me this? OMG, could it be in the manual?