There doesn't seem to be a way to list chat rooms beyond the first 100 that are returned in the chat room list. Could you please add a way to get the next set of X chat rooms?
From pidgin:
Buddies->Join a Chat...
On dialog, click Room List button
Only first 100 rooms are shown. No way to get more that I can see.
This seems to be an implementation limitation on the server side or pidgin.
The specification [MS-XCCOSIP] doesn't have a "maximum entries per response" value for chat room search, nor does it have any provision of "request more entries" in the response. SIPE doesn't limit the number of entries either, it simply scans the response and forwards each entry to the backend.
If you add a --debug log (the cmd:chansrch & rpl:chansrch messages might be enough) then we could decide which one has the limitation.
You are correct, even using the offical MS Group Chat client there is no way to get the "next" or "more" chat rooms. The official client does however have a search field which is used to limit the results to chats matching the search.
It doesn't look like the pidgin room list has any type of search functionality to tie into, but maybe I am just overlooking something.
I am hesitant to post debug logs as there is company information in there. Is there anything in particular that you would need?
Thanks for confirming the same behaviour in the official M$ Lync client.
You'll need to file an enhancement request against the Pidgin project to add a "room filter field" to the room list UI plus the necessary extensions to the protocol plugin API. After this is available then SIPE can be updated to forward the filter string to the groupchat search channel message.