Transfer Data from Click Event Between Bokeh Apps
The cookies idea might work fine. There are a few other possibilities for sharing data: 

a database (e.g. redis or something else, that can trigger async events that the app can respond to)
direct communication between the apps (e.g. with zeromq or similiar) The Dask dashboard uses this kind of communication between remote workers and a bokeh server.
files and timestamp monitoring if there is a shared filesystem (not great, but sometimes workable in very simple cases) 

Alternatively if you can run both apps on the same single server (even though they are separate apps) then you could probably communicate by updating some mutable object in a module that both apps import. But this would not work in a scale-out scenario with more than one Bokeh server running. 
Any/all of these somewhat advanced usages, an working example would make a great contribution for the docs so that others can use them to learn from.
I have two Bokeh apps (on Ubuntu \ Supervisor \ Nginx), one that's a dashboard containing a Google map and another that's an account search tool.  I'd like to be able to click a point in the Google map (representing a customer) and have the account search tool open with info from the the point.
My problem is that I don't know how to get the data from A to B in the current framework.  My ideas at the moment:

Have an event handler for the click and have it both save a cookie and open the account web page.  Then, have some sort of js that can read the cookie and load the account.
Throw my hands up, try to put both apps together and just find a way to pass it in the back end.