[DataEntry] Entering data slows drastically as RecentEntries grows

[imnasnainaec]

As reported by Sara M:

We started using Combine with our Field Methods class this morning. This was our workflow:

1. enter into chosen domain
2. language helper typed in the vernacular field as many words as he could think of for the domain
3. student types English gloss into gloss field for one entry
4. student clicks with the mouse in whitespace (this causes the record to be saved)
5. create audio recording for that one entry
6. repeat 3-5 until end of list

The first group of students collected 30 entries (across two domains); the second group had 44 entries in a third domain. By the time the second group were about half way down the list, trying to get glosses and recordings, each time after doing step 4 above, there was a definite lag of several seconds whilst the record was committed. Both students and the language helper were somewhat frustrated by the lag.

The same lag grows entering vernacular and glosses at the same time and not editing any of the recent entries.

[imnasnainaec]

Improved by #2752.