Glad to know I’m not the only one!
Found a “fix” on another site that consists of adding custom CSS to your theme:
html{height:100%;}
body{height:100%;overflow:hidden;}
#page{position:absolute;overflow:auto;height:100%;width:100%;}
I find that only works in themes that have a “Custom CSS” option built into their customization. Otherwise, it doesn’t seem to do anything.
It’s not really a fix, though, because that code kind of wrecks your theme, and sends your footer and header and everything else to places where they shouldn’t be. I’d use it cautiously.
If anyone finds a real fix, that’d be swell.