Last modified: 2014-10-22 19:07:37 UTC
When adding/modifying a template, you can append a space to the parameter, and even if you have that parameter already used, you can add one more. As well you can add a (multiple) empty " " parameter. Example template I made ended up as: {{test|name = " |logo = ' "| = | = |logo = }}
Clarification: the transclusion dialog allows the user to create both "foo" and "foo " as separate parameters, but it shouldn't. It also allows the user to create the empty parameter (" ") multiple times.
This appears to be fixed now. You can't create both "foo" and "foo " any more.
