When you add additional objects into the selection, you may find that the previous selection is canceled and only your latest selection is kept.

You may be wondering why you can’t select multiple objects, actually this happens when you have changed your PICKADD value, which controls whether the newly selected objects become selection set and the previously selected objects are removed from selection.

By default, the PICKADD value is 2, which adds each newly selected object to the current selection set. There are three simple ways to fix your problem.

1. Enter PICKADD, enter 2 and press Enter key.

2. Enter OP to open the Options dialog box, and uncheck the checkbox of “Use Shift to add to selection”, shown as below,

3. Use CTRL+1 to open the Properties Panel, there is a ”1” button at the upper right corner, shown as below, which means only one selection set is kept at a time.

We can click this button to switch it to “+”, which enables more than one object to be selected to the selection set.