Thanks Ashley. Glad you understood what I meant even though I misworded text and textbox. That perfectly describes what I was experiencing. The good news is, for my purposes, with WebGL turned off, the maximum text plugin size seems to be unlimited. And because the textbox plugin uses scrollbars with no way to detect if they were visible, and no ability to resize the box based on the text height, it was totally unsuitable for my purposes
I uploaded my app to the Scirra Arcade (even though it's not a game and didn't fit into any category) you can test it out in the new games/other games. It's named uPrompt Nomad (sorry, can't link yet)
As a test, I copied and pasted Moby Dick into the editor and the text plugin was able to display and scroll the entire novel in the text plugin with the font size at around 50px. It was a bit laggy but that test is an absolute extreme of what I'd expect it to do.
Thanks for confirming that WebGL wasn't going to work.
And thanks for C2! Along with being a shareware author, I'm now an app developer. I have just published this privately on the Chrome Web store as a free app and will be uploading the paid app in the next few days. Android and other platforms are soon to follow.