Some Demos require multiple screen shots in the docs

Ref: #1574

The script for regenerating screenshots for the documentation needs to be updated (or separate script(s) added) to special handle the cases where we need multiple screenshots from one demo.
For example the TextEditor demo has 3 separate tabs for integer, string, and password text, that each should have its own screenshot. Likewise there are cases where we want screenshots of the context menu that pops up after clicking something, or the color editor popping up a different color selection dialog, etc.

Ideally, the script(s) can be run and _all_ the needed screenshots will be regenerated.