As I read in another post, if you close FTM without first closing your tree you may run into this extremely small font problem (I did). You need to get into the habit of opening FTM, open your tree, do your work, close your tree, close FTM.
I've set my Windows font size to custom size 149%. If I use the Windows standard 150% I experience problems with various programs - like the right portion of the window not showing on the screen. If I use 149% I don't have that problem.
With FTM 2014 I'm using the Window's 149% and FTM's no caps [I meant no "Use large fonts"] with only minor issues with FTM fonts - the bottoms of the parents names in the Family Group View panel disappear (but the names are still readable) , the name you are on in the Index panel disappears (but is viewable in the Tree Viewer) and the name in the Editing panel is shortened. Until FTM fixes this bug this is the best solution I've found for my poor eyes!