This is something that I think really really really needs to be addressed.
When you're in a Fleet Action, it's almost impossible to coordinate any attacks...especially in the Crystalline Entity mission. The main reason for this is that zonechat from every single instance ends up in the same window. There doesn't seem to be any way to "lock" things so that you're only seeing messages from your specific zone.
Do you have any idea how hard it is to set up tactics when completely different tactics are being shouted out from every single other instance? With up to 21 people per instance? Chaos very quickly reigns. People start talking in all-caps to try and get their point across, people in a completely different instance are yelling at the person who is typing in all-caps because it's interfering with their attempts to say anything to their fleet action teammates, zonechat itself starts whizzing by at about warp 5, so you miss the messages meant for you and instead see people spouting bad advice...it's a mess.
I know that the shared zonechat makes it supposedly "friendlier" in that everyone can talk to everyone else regardless of which instance they're in, and I suppose that works fine for sector space...but honestly, it's an incredibly dumb way to have chat work when you're in something like a fleet action. You can't get around it by teaming, since a team can only have five members and there's no way to "link" teams via a raid interface, most fleet actions are pick-up (especially since there's a cap on how many people can be in each instance, making it hard for a fleet to all end up in the same one) and so you can't really coordinate via voice chat, and local chat only works if you're close enough to the person talking to actually have it show up on your screen.
Please, just give us the option to set the chat to "own instance only" or something like that. It'd make life so very much easier in those fleet attempts. (And probably in PVP as well, although I don't participate in that so I can't say for certain. I do remember that when testing it in CB both factions ended up in the same zonechat...does that still happen? Seems designed to make you avoid tactics, if so. XD )