The following code produces a filled loading SVG:
<div style={{color: '#bf0711'}}>
<Button plain monochrome loading disclosure>
Try again
</Button>
</div>
Not having a square.

Use the code state above.
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Looks like once loading to this combination of props, it visually breaks:

changed the title ~Button, plain, monochrome, disclosure & loading is borken~ Button, plain, monochrome, disclosure & loading is broken
but borken was so much nicer 馃槶
I prefer borken as well 馃槃
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Still an issue
Most helpful comment
changed the title ~Button, plain, monochrome, disclosure & loading is borken~ Button, plain, monochrome, disclosure & loading is broken
but
borkenwas so much nicer 馃槶