Needing a change of pace this weekend I spend the last two days cobbling together a C# WPF program that I'm calling AesPad. This little text editor (as if we needed another one) saves all files with AES encryption. It uses a password-based key, so the onus is on you to not use a low-entropy password. You enter your session password right from the start and the editor will try to use this password to encrypt and decrypt files. You can change your session password whenever you wish. It should be noted that if you have an open file that has already been saved with one password, then change your session password, it will warn you upon the next save that you're changing the encryption password. I also decided to use a custom file extension .aspd so the program can be associated with the created files. The program is restricted to only open and save files with that extension.
There's not much else to say here, so I'll leave a screenshot and a download link: