Renaming instrument is very slow on complex scores

When renaming an instrument in MU4, the instrument name is updated on every keystroke, which in complex scores is fairly slow. In complex scores, this causes very long delays between keystrokes and seeing the input reflected either in the text box or in the score. This affects both the long-form and abbreviated instrument name fields.

1. Open a complicated score, like the one attached
2. Under the Instruments panel, click the gear icon, then click on either the full name or abbreviated name
3. Type

On my system for the attached score, each keystroke takes about 1 second to input, so when typing it has the effect of making my input invisible until well after I'm done typing.

A simple solution, and the behavior I expected, would be that the rename would only be committed to the score, triggering relayouts and such, after I'm done typing. That could be done many ways, like listening for the dialogue losing focus, adding a 'save' button, or even simply debouncing the keystroke handler.