I am sure this worked in the past…
reproduce: Draw some Lines / Arrows + a text, group everything and try to mirror this
the elements alone can be mirrored
Version: 5.3.7.2.0+
Build-ID: 5.3.7-4
CPU-Threads: 4; BS-Version: Linux 4.12; UI-Render: Standard; VCL: gtk3; Layout-Engine: neu;
Gebietsschema: de-DE (de_DE.utf8); Calc: group
Hmm even if I do not Like Visio this much, the default behavior of visio here is much saner…
it would first allow mirroring without convert to polygons (which means loosing the ability to edit),
further it would place the text object to the correct mirrored position inside the mirrord group,
plus it would not mirror the text (if it was readable before, it will be still readable)