No, there's no way to change that. It's pretty standard user-interface behavior on Mac and Windows. If you accidentally delete, you can always type Ctrl/Cmd-Z to undo.
Thanks John. I had a feeling it was more the OS than LR, but it doesn't happen universally in all applications. But maybe I'm thinking more of web forms.
I know I can undo, it's just that it's annoying to have to A) be extra careful not to overwrite and B) click a second or even third time to get the cursor where I want it. Oh well, "first world problem" I guess...
Interestingly, though, it does NOT happen in the Enter Keywords field.
it doesn't happen universally in all applications
Right, it's an often-used but not universal idiom.
click a second or even third time to get the cursor where I want it
Yeah, you have to pause before that second click, or else it is ignored. That is minor irritant to me too.