This seems to be a tricky one ... more details:

It only happens when the tool menu is set to only select own objects.

The pie menu does a temporary selection which highlights objects regardless of the setting.

When the inspect window opens first time, it takes the focus. The pie menu then clears the selection based on the setting, i.e. when "only own objects" is on, the pie menu makes the selection go away and when the inspect window looks at the selection, nothing is there.

If anyone likes to work at this, let me know and I'll give you the tech details.

Patch description:

The problem in 1.17.2 is that the pie menu (right click) allows to select items despite the "Only select own items" setting. However, when inspect opens, the pie menu loses focus and then does a valdate-select which only leaves valid selections, i.e. with "only select own" it deselects the content that was previously selected and for which the Inspect window was called.

The easiest way to work around it seems to be to use the gSelectMgr->setForceSelection function, which prevents the deselection when the pie menu loses focus. So it is just necessary that force-selection remains enabled until the Inspect window has it's focus and has it's tool in place.

I added a paramter to setForceSelection to return the previous state (this is probably not strictly necessary, setForceSelection(TRUE) and setForceSelection(FALSE) would do also, but I like to play safe here).

I also rearranged the code for LLFloaterInspect::show() a bit for more clarity, which unfortunately makes the patch itself less clear. So I'm also attaching a file with the full function before and after the change (it's just about 12 lines) and should make the change sufficiently clear.