Because of the same priority with emptyBaseLayer.directive, expandable.directive on line:
var rowRepeatDiv = angular.element($elm.children().children()[0]);

Gets the rowRepeatDiv of wrong element:
div.ui-grid-empty-base-layer-container.ui-grid-canvas
instead of:
div.ui-grid-canvas (which is the second element of the array - $elm.children().children()[1])

Becouse of that, sub-rows wont get rendered. Raising expandable.directive priority fixes the rendering.

Is it a good case for a pullrequest? Or is it because of my configuration?
I also use:

• ui-grid-pagination
• ui-grid-auto-resize
• ui-grid-selection

I tried ui-grid-empty-base-layer="false", but that didn't help.