This fixes an issue when destroying VST plugin UIs
rather than hiding them. Even though is hidden before destroying it,
the vistracker is also destroyed in the same function call, before
the event can be processed. The window state remains visible="1"
Re-assigning a sigc::connection does not disconnect
any previously connected signals.
WindowProxy::setup may be called multiple times. Notably plugin
windows can change the managed _window (generic/custom), which
requires a call to setup.
Actions for hide/show/attach/detach tabbables use hard-coded names which are not
translated. Using Tabbable/WindowProxy::name() to lookup the action will fail,
since the name can be translated. This changes just removes the option to not
provide a menu-name when creating these objects, and uses the name menu-name
when looking up an action by name
eg. LV2 externalUI windows are not managed by ardour; Ardour cannot
intercept mapped() or delete_event() signals and hence also not
create a visibility-tracker.
First call to WindowProxy::toggle() creates the window, and the 2nd call
crashed since 6ca8ec5141, due to missing vistracker.
e.g. externalUI plugin windows, the processor-box uses WindowProxy
for all plugin-UIs incl. externalUIs.
This fixes inconsistent WM::Proxy state when a window is destroyed
Specifically "session-options-editor" when the session is unloaded;
previously "toggle-session-options-editor" was never unset.
I would have loved to split this apart, but there are just so many interrelated changes,
it makes little sense and would be a huge effort that would break future git bisect
use because so many intermediate commits would not compile
