Wai-Aria: Unable to shift-tab out of widget


I am creating some grids made accessible by wai-aria. They work extremely well so far, but the problem I am having is that once you are in the grid, it is impossible to shift-tab out of it. I don’t know if I need to manually handle this in Javascript, or how I would do so, or if something else needs to be done.

Any help would be appreciated.