I'm using Metashape Standard Version 1.8.4.14856
So, this is an issue I have been encountering since about mid-2022. Prior to around this time, when I wanted to clean up my mesh clouds I would use the Selection tool over the mesh I wanted to remove and it would all be gone once I hit delete. Now though the selection will delete all or most of the selected mesh but often leave behind little clumps of mesh that I'll need to zoom in and then rotate around multiple times to fully delete. This is in addition to very small bits of mesh that don't get wiped with a broad selection and sometimes these will require me to look at them in a very specific angle to delete.
I have attached two examples. The second image is the result of my using the selection tool over everything aside from the head effigy, from the front of the model.
Thank You