This feature doesnt work when there's two servers connected, order of connection to server is irrelevant not sure about nr of channels in each server. I have two channels on freenode and one on efnet, as follows.
Connect Freenode, #channel-1 #channel-2
Tiling works ok any combo pressed changes to whatever you select.
Connect to efnet, #channel-1
Tiling no longer responds or works in any selected server.
Cascade is the only one that works.