This is a new feature in version 6.50.
The Preferences form has changed, somewhat, in that there are now 'Save' and 'Cancel' buttons, so any changes you make do not take effect unless you select 'Save'. This is the design that always should have been there from the outset, of course, but maintenance of this form has always been at the bottom of the priority list.
This explains, in part, why I had gotten to the point where I so hated the thought of adding new features that required preferences, and also why there was so much work to do to use the new object (created as part of the re-factoring expedition), which handles all of the preferences. Currently, there are about 135 preference items for it to maintain.
There are only a few new options in the new release:
Check out files using Source Control - 'General' tab, 'Processing' sub-tab.
Reset filters when opening another class or form - 'Filter Defaults' tab
New hot key Dynamic Snippets - 'Hot Keys' tab