Weird behavior of name field of new first-level taxonomy categories

When creating a new first-level category inside a taxonomy, and changing the Name: field before saving the document, each key-stroke has the effect that the cursor jumps to the start of the input field, effectively inverting what you type.

This problem is gone after Save-ing the taxonomy, and it doesn't occur on pre-existing first-level categories, or on categories which are more deeply nested in the taxonomy.