Behavior of "Dump across banks" is inverted

[foone]

The checkbox on the Save Memory Range labeled "Dump across banks" seems to act as "Dump only selected bank".
if I do a dump with start address [-1]:[0] and byte count [0x80000], the resulting file is 16kb if the checkbox is checked, and with the same values I get a dump of 512kb bytes if unchecked.

Version: mGBA 0.8-b1
OS: Windows 10 64bit

[foone]

although now that I look closer at the files it's even weirder.
when it's unchecked, the length is right, but all the extra bytes >16k are 00.

[endrift]

What system? GB or GBA?

And yeah I didn't describe it well. Being terse can be hard.

[foone]

It was gba.
Although now that I'm thinking about it, the file being mostly empty may be my own fault, and I'm just not understanding the GBA memory map.

[endrift]

I believe more than anything this is a documentation bug. If you select "dump across banks" it's supposed to dump all the banks of the same region (up to the length selected), e.g. ROM on GB isn't all always mapped. Thus it ends early if the range is greater than the size of that region. If it's unchecked it just reads raw bus memory, which may entail dumping multiple regions in the range given.