Before contributing to the MESS MC-1000 emulation, I worked with another MC-1000 emulation implemented as a Java applet. To it I added some clipboard operations that have been proving very useful: 1) Copying/pasting a (plain text) BASIC program from/to the RAM (where it is tokenized). 2) Copying/pasting blocks of bytes from/to the RAM (or VRAM). 3) Copying/pasting the content of the text screen.
The ability to "inject" program and data directly from the clipboard, without resort to "tape" files, is very helpful while you are developing a new program.
What do you think?