User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20160912030421 Steps to reproduce: See the attached float.html Actual results: Every rectangle should respond to the mouse over event, only one does. Works on Chrome.

working with integer values only doesn't cause this problem (but I can't use it in my project because I'm depending on other libraries that expect floating point values to work).

I think it's a precision issue, if at any time in the scale conversion any of the position attributes becomes too small (~<0.0001) it gets truncated and doesn't get "scaled back up" from the DOM's point of view although it gets displayed properly.

Hello, Any progress on that? This is causing major usability issues with libraries like OpenSeaDragon... F.

I'm getting the same results here as in bug 1167959 - the role of the viewBox transform in that bug is being played by the scale transform on the <g> in this bug. (I'm also seeing an identity transform on the anonymous child, but I guess that always happens since bug 1458968.) The testcase here includes the relevant 1/60 grid points discussed in bug 1167959 - the yellow one was the one I hit in a test run.