Wow, this is very nice. I've been using Stickies 9.0c for a while to make notes for specific web pages or documents, but, your program is much simpler. Stickies has Rich Text with bullets, bold, italic, etc., but, for the most part I have no need of text formatting. Stickies has a myriad of other features but a lot of it is overkill.
What do the stickies match on: app name, window title or some other combination? I'm just curious. I will be working with Stick A Note.
Stickies stores Window Title and Program Class and allows you to use asterisks wildcards in the Title.
So, in Firefox, if you wanted a sticky to make notes for any YouTube videos you watch, you can enter:
You may want to allow users to not match the full Window Title and enable wildcards to make your program much more versatile.