FreeCADI was working on my feature the other day, and exploring the FC coin selection code. I found that FC always requests for pick point list for each mouse click, to solve a priority issue (vertex over edge if the click point hits both). I needed some kind of pick point filtering also, so I thought why not enhance the FC selection API to bring out this pick list. I remembered having trouble selecting certain obscured subelement in the past, so this must be a useful feature. So I went ahead, and finished it. You can now request Selection API to give you the pick list on each click. The list is available through Python and SelectionView. I was happy until I found this annoying problem. When the element is either pre-selected or selected, it becomes opaque, so how can the user select the obscured subelement if he cannot see? Err... I am feeling stupid now. I digged into Part rendering code to try to solve this problem, but failed to came up with a solution. The delicate transparency rendering is apparently handled by Coin itself. Any coin expert here can come to the rescue? @wmayer?
Or, maybe we can have a way to disable preselecting temporarily. But which key to use? Ctrl, Alt, Shift all have special meaning during mouse movement. Any suggestions?
