Empty line on items not Canceling/Removing line

Not sure if anyone else is noticing this, so was hoping someone else could confirm. This is in a standard sales order.

I have a validateLine function returning true.

I do the following:

Add a line item value with quantity and rate and click add
Move to new line.
Do not enter an item but change quantity to a value (22).
Then try to Add and get message "You must enter an item...". OK, as expected.
Then try to just click on the line entered above. Same message. OK, still good.
Go to the line without the item and click the Cancel. The quantity clears as expected.