Chrome 46.0.2490.4 on OS X 10.10.5 Resizes Wrong Window

With the last few updated on the Chrome (dev) tree, and certainly with 46.0.2490.4, when I select the resize "button", and select a size, a completely different window (still Chrome) is resized. It's repeatable, in that it's the same "other window" that's resized, and if I go to that window and resize it (with the extension) it works as expected.

Yet it's not possible to resize any other Chrome windows. It's like there's a "stack" and the "top" window gets the resize message - regardless of which window is used to "active" and "select" the resize.

This was working fine for months and months - so I have no doubt it's something about recent Chrome releases, but what, I don't know.

All the resize settings are "Window" resizes. They all only set the size - and don't move the window at all. This is a Retina MacBook Pro with two external monitors - but it doesn't matter where the window is when this happens... the same (wrong) window will get the resize event. Regardless of the size selected.

If there is more I can provide to help in debugging, please let me know.