Previously it was, for example for SUM,

1
2
3
...
28
29
30,31,32,33,...,253,254,255

ie. for more than 30 parameters the exceeding ones were crammed into the last
(30th) edit field. The expression still worked, but this was ugly, and
selecting the last field it was easy to overwrite all remaining arguments at
once.

Change-Id: I6b27a20e7f07d3a6b4752855f04d6239e6375418