Percent sized containers and toggle buttons with some browsers are broken

[bpatra]

Let us say I create the following container layout

<div ui-layout="{flow: 'column'}" >
  <div ui-layout-container size="30%"></div>
  <div ui-layout-container></div>
</div>

which is a vertically separated layout with one slidebar and the first left item is 30% of the container.
Then, after toggling to make first layout container disappear (the one with 30%) and toggling again to open it, the displayed size is incorrect. Indeed the 30% has been interpreted as 30px!

See reproduction case http://plnkr.co/edit/UvhJOo3WxHjdpY0huCuk?p=preview
Angular ui layout: 1.4.3
Angular 1.4.10

Reproducible deterministically with Firefox and MS Edge, randomly with Chrome.

Note that the collapsing of right section is broken but it is another bug, the issue #209

Seeing this issue even with fixed size in pinxel on chrome.
e.g: size="28px"