Data field emptied on field type change

[adrian]

I think there is a bug that exists when you change a field's type. The contents of the data field in the 'fields' db table is deleted. Most importantly (for me at least), is the tags.

[ryan]

When you change a field's type, it doesn't keep the configuration settings for the old one around. That's because the new one may have very different settings or may conflict with the new one. So it's safest to start fresh on this. Tags is one that could feasibly stick around, so maybe we'll find a way to do that in the future, but for now we reset the field's settings when you change it's type.