TurboTax left EIC line 4a blank

We have two kids, qualify for EIC, and TurboTax has assessed it properly.

 

However now I am reviewing the forms before filing, and I see that Schedule EIC line 4a has been left blank. The rest is filled in appropriately. The EIC form has a warning from the IRS to "fill in all lines that apply to each qualifying child."

 

It seems like I should check "Yes" for both kids. But in "forms" mode in TurboTax, if I try to click those boxes, an "X" only appears while clicking - then disappears as soon as I release the mouse button.

 

Do I need to check those boxes? How to get TurboTax to do so?
Thanks,

-Daniel