When the Reuse all tools option is on, tools windows are reusable by default. However, it is possible to specify that a particular instance of a tool is not reusable. To make your Inspector not reusable, follow these steps:
The Reuse all tools option is persistent, but the per-tool setting Resuable applies only to the current instance of the tool, and it does not affect future sessions.
LispWorks IDE User Guide (Macintosh version) - 25 Nov 2011