Password Safe v3.33 does not allow password generation rules that include at least ZERO special characters, upper case etc. Either I enable that type of character and get at least one, or I disable that type and get none. However some web sites allow but do not mandate special characters etc. Ie the rule for those sites is at least ZERO, so it would be nice if Password Safe could match that. (A rule of "at least one" reduces the number of possible passwords, when compared to "at least zero".)
If it's not technically feasible to implement "at least zero", then the dialog should not not allow the "at least" spin box to go to zero. Currently, it will accept a zero, but then not remember or use it - it either goes to 1, or unticks the box.