Adding tools to toolbox. Is the number limited?

[ian.bishop]

I have been trying to add tools to the standard toolbox. When I try to add one it wont drag across from the customise window. BUT if I delete some tools I can then add more. It is acting as if there is a limit on tools in the toolbox.

[Nigel Pearce]

There is no limit. See attached image. I assume you are drag/dropping them onto the main toolbox?