When you have defined contexts and you start mu4e it decides which
context to use based on the variable mu4e-context-policy;
similarly, when you compose a new message, the context is determined
using mu4e-compose-context-policy.
For both of these, you can choose one of the following policies:
always-ask: unconditionally ask the user what context to pick.
The other choices only apply if none of the contexts match (i.e.,
none of the contexts’ match-functions returns t). We have the
following options:
ask: ask the user if mu4e can’t figure
things out the context by itself (through the match-function). This is a
good policy if there are no match functions, or if the match functions
don’t cover all cases.
ask-if-none: if there’s already a context, don’t change it;
otherwise, ask the user.
pick-first: pick the first (default) context. This is a
good choice if
you want to specify context for special case, and fall back to the first
one if none match.
nil: don’t change the context; this is useful if you don’t change
contexts very often, and e.g. manually changes contexts with M-x
mu4e-context-switch.
You can easily switch contexts manually using the ; key from the main screen.