SetStyle will tigger a resize event, which in turn will start the
m_aPanelLayoutIdle, before it's actually prepared, resulting in
the Task::SetPriority SAL_WARN_IF triggering.
Change-Id: Ide48d6004e242cf75bb48dc9f5e8dc3aa5ff809b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97664
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
