Bugzilla

There's a couple of reasons to do this:
- There are a couple of bugs (bug 1596725, bug 1596947, preferences main stack) that were caused by the `min-height: auto` behavior on the grid items which takes in account the implicit height of the content inside it. This caused some boxes to not be restrained by height of their parent. 
- The default `min-height: auto` for grid items is more expensive than `min-height: 0` to compute since it takes in account many factors. This may be a way to address the TART regressions being seen in bug 1596416.
- XUL <stack> was designed in a way where the dimensions are usually already decided by the parent element, whereas CSS grid is more designed in a way where content decides the height, so `min-height: 0` might make more sense here.

There's a couple of reasons to do this:
- There are a couple of bugs (bug 1596725, bug 1596947, preferences main stack) that were caused by the `min-height: auto` behavior on the grid items which takes in account the implicit height of the content inside it. This caused some boxes to not be restrained by height of their parent. 
- The default `min-height: auto` for grid items is more expensive than `min-height: 0` to compute since it takes in account many factors. This may be a way to address the TART regressions being seen in bug 1596416.
- XUL <stack> was designed in a way where the dimensions are usually already decided by the parent element or the element itself, whereas CSS grid is more designed in a way where content decides the height, so `min-height: 0` might make more sense here.