We just updated our Unicode Character Insertion utility CatchChar to version 1.5. This version supports running from a portable drive. But to get that capability, please do not install to a portable drive. It won’t work that way. Instead, follow the steps given in the product page of CatchChar.
That means, you can now run CatchChar from a DropBox folder too and it will be available on all the computers connected to the DropBox!