moving through numeric entry fields with tab-key

Dear Community,

 

I have a question regarding a set of numeric entry field I included into a storyline slide. Now, to move from one field to the next i usually use the tab-key. This works just fine for the first entry fields, then the tab jumps over one field and in the end leaves out another one. What can I do to solve this? They fields are all arranged one after the other in the timeline... And I have no clue how to fix this.

So, I'd be grateful for advice! Thanks in advance!