i'm quite ok now with webOS 2.2.4 but what always slows me down is that in Messaging you can just type to find a conversation by entering the reciepient name (e.g. John Doe) but not if you just enter the two initial of the name.
So if i enter "John" it works, but if i enter "JD" it won't find John Does conversation like in Contacts or "JustType".
I thought it worked in older webOS versions, but i'm not sure.
I could only find a Knowledgebase entry of contacts so perhaps it was never there in messaging:
Palm Support : Palm Pre Plus for Verizon - Using Contacts
Finding a contact
Open Contacts .
Enter any of the following:
First, middle, or last name
First and last initial (no space between) even better if two or more letters from last name.