I'm currently using QCad version 18.104.22.168 and have the following question.
The manual states the following:
The other icon beside the layer name is a symbol for a lock. In Figure 14, layer "hatches" is locked. Entities on locked layers cannot be selected and therefore cannot be modified or deleted. To quickly lock / unlock a layer, click on its lock icon.
If I create a layer and lock it so that I believe that I can not do any editing of any kind on that layer I find that this is not true. I can add new entities and modify those but can not select or delete them.
Although I can not actually select an entity when I lock a layer - I can still Trim/Extend and Trim to an Intersection - add a chamfer or radius these entities which are supposed to be un-editable. Does any one know how to lock a layer totaly so that you can not edit on a locked layer.