the best thing about ghidra is that no matter which version you're using, setting equates sometimes just doesn't work, but if you google it, you only find several bug reports which basically say "equates don't work" and then it's "closed, fixed in X.Y.Z" and that's a version you're upgraded way past

port_out(0x3c4,0xf02);

I SO WANT TO EQUATE 0x3C4 TO THE VGA SEQUENCER INDEX REGISTER BUT I CAN'T

the weird thing is the equates table says it's been set, says there's a reference to it at that address, but if I go to that address, there's nothing. just 0x3c4
OH GOODY I found a mistake in OSDEV
their docs on the PC gameport are incorrect
and I can't rename some local variables either!?
what the fuck, ghidra?
@foone FWIW, I believe in IDA this kind of thing mostly happens because they want to attach the new name to _something_ in the assembly code, so when the decompiler has introduced the variable, it's often not clear what it should be attached to, and things get weird and broken.
@dougall yeah I've had that happen. Not here, though. The variable it can't rename is just a standard register