Qt.createComponent is asynchronous, but a widget was only recorded in
pluginWidgetComponents once its component finished. syncPluginWidgets runs
several times while the shell starts, and every pass that ran while a load
was still in flight could not tell it apart from one that had never
happened — so it started a second load of the same URL. All twenty bar
widgets were loaded twice.
The duplicate component then replaced the first in the registry, and
swapping a slot's component makes its Loader build the replacement before
dropping the original. Both were briefly live, and both registered the
widget's IPC handler, which is where the "another handler is registered
for target" warnings came from.
Claim the key when the load starts instead, and release it if the
component fails so a later rescan can retry.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
