Report objects who sharing a material to avoid lightmap problem

[cstfan]

If 2 objects share the same material

there will be a problem when we apply the lightmaps.
With this report, we can check to the scene is ready for LM.

Maybe the same button for this report and this #52.

To avoid this, you can of course type Make Single User in Search and choose Material

[Vinc3r]

'could be nice to have choice between change objects selection or just made a report

(these buttons could be use in other parts of the addon)

[cstfan]

To also have the selection would be top