I'm creating a fairly basic script which allows me to select the faces of a mesh in scene view. I got it working for single click selection. However, I'm wanting to implement multi-selection using a modifier key or via mouse drag (similar to ProBuilder's face selection ability which I can use but is overkill for what I need). My problem is that whenever I use a modifier key (Shift, Ctrl, Alt etc) or drag the mouse over the object when it's selected the object get's deselected in the scene. When I click back on the object the faces have all been selected. So the multi-select feature works. I'm wondering how I can have it so the object remains selected whilst performing those functions?