User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0 Build ID: 20120420145725 Steps to reproduce: We have .js-communication-iframe to hidden iframe. .js-communication-iframe { height: 1px; left: -1e+7px; position: absolute; top: -1e+8px; width: 1px; } If we remove top: -1e+8px; every thing is okay! Actual results: When iframe with this class is rendered the y-scroll disappears, and can't scroll

From https://developer.mozilla.org/en/CSS/calc#Examples it seems the code needs some adjusting to work.

Mardeg: this is unrelated to calc(); it's scientific notation. Oleg: do you have an HTML file that shows the issue? That would he really helpful.

That CSS Code was from firebug, here is the original: .js-communication-iframe{ position:absolute; left:-10000000px; top:-100000000px; height:1px; width:1px; } Unfortunately I can't provide HTML, because it's on our DEV-Server, and all CSS are loaded from it.

(In reply to Ms2ger from comment #2) > Mardeg: this is unrelated to calc(); it's scientific notation. Sorry I misread -1e as -1em

-100000000px overflows our internal representation for coordinates. I don't think we give any guarantees whatsoever what the layout will be in such cases. Just use a smaller number for now, -100000px should be OK.