Impossible to add SoftCredit row once deleted on New Contribution form

Steps to reproduce the bug:
1) Go to 'New Contribution' form and keep adding soft credit entry by using 'add another soft credit' button
2) Then the 'add another ...' button will disappear once it reached maximum entry limit (i.e. 5)
3) Delete any row but then the 'add another ..' button won't appear again or there is no other alternative to add another entry.

(Fear factor: Once you delete all the row there is a blank Soft Credit block with no SC entries)