Controlling AutoCAD selections with PICKSTYLE
When making entity selections in AutoCAD, sometimes the results can be unexpected. You may select a hatch object and move it its associative boundary stays put, or you may erase a line and other geometry disappears with it. Situations like this can be controlled by a system varible named PICKSTYLE.
PICKSTYLE controls two things, how associative hatches and their boundaries behave and how grouped objects behave. Let's take a look.
PICKSTYLE = 1. The green and red circles, together with the blue star are part of an AutoCAD Group. When I select the green circle, notice that Properties says all 16 entities are selected.
Below is the same green circle selected while PICKSTYLE = 0. Notice that Properties confirms only the single object selected. No change was made to the grouped objects, they are still a group.
With associative hatches, notice what happens when I pick the magenta hatch while PICKSTYLE = 2, both the hatch and the green boundary are selected.
Now I'll pick the same magenta hatch with PICKSTYLE = 0, only the hatch is selected.
Hopefully that helps explain the various PICKSTYLE settings. To recap, PICKSTYLE = 1 allows for group selection. PICKSTYLE = 2 allows for associative hatch selection. PICKSTYLE = 0 disables both. There is one more setting of PICKSTYLE = 3, which allows for both group and hatch selections. It is basically combining the setting of 1 and 2.
You can toggle group selection on and off from the keyboard with either Ctrl+Shift+A, or Ctrl+H. This shortcut will toggle PICKSTYLE between 0 and 1 or between 2 and 3, depending on the initial value. PICKSTYLE is saved in the registry, so it won't change from drawing to drawing unless you have some external program changing it.
One last note. Whenever you have more than one object selected such as the hatch and boundary above, you can use the drop down box in the properties dialog to filter your list down to one or more items as shown below.