When point is just after the slime prompt and the user does M-x hyperspec-lookup, the prompt is inserted into the minibuffer as a suggestion. Text properties are retained, and so the user cannot delete the suggestion or even select the previous history entry.
Here is a patch that corrects this problem by stripping all of the text properties from the suggestion. A big hammer, perhaps, but I don't like seeing randomly-coloured text in the minibuffer anyway.
Index: hyperspec.el =================================================================== RCS file: /project/slime/cvsroot/slime/hyperspec.el,v retrieving revision 1.10 diff -u -r1.10 hyperspec.el --- hyperspec.el 28 Oct 2006 08:44:41 -0000 1.10 +++ hyperspec.el 6 Dec 2006 21:08:16 -0000 @@ -83,7 +83,9 @@ Visit http://www.lispworks.com/reference/HyperSpec/ for more information. If you copy the HyperSpec to another location, customize the variable `common-lisp-hyperspec-root' to point to that location." - (interactive (list (let* ((symbol-at-point (thing-at-point 'symbol)) + (interactive (list (let* ((symbol-at-point + (substring-no-properties + (thing-at-point 'symbol))) (stripped-symbol (and symbol-at-point (downcase