Summary:
Pickblocking ferns when having a grass item in hotbar, and no fern item, selects the grass item. Note: Pickblocking a fern without grass in hotbar yields expected result.

Step to Reproduce:
Pickblock fern while having a grass item in hotbar and no fern item.

Observed Results:
Selects grass item.

Expected results
Fern item should be given instead of selecting grass.