This is a bit of a mystery. While working on bug 817836 I discovered that if you call listTabs twice (once on toolbox-ready and once from within the makeRemote for example) then the following webconsole tests fail with some weird errors like 'value was not discarded': [X] browser_bug_869003_inspect_cross_domain_object.js [X] browser_webconsole_bug_600183_charset.js [X] browser_webconsole_bug_630733_response_redirect_headers.js [X] browser_webconsole_netlogging.js I worked around this issue in the aforementioned bug but the whole thing still seems to be very fragile.
Did you investigate to see why they actually break? They all seem to relate to network logging (in the console actor), or tab navigation (in the tab actor).
I attempted (and so did dcamp if I recall correctly) but when I discovered the workaround I decided to focus on finishing my console.profile bug instead. So far it seems like one of the listTabs calls somehow sets all those properties such as discardProperty but I couldn't find where it happens in the code. Sorry for not being too helpful.