Hi,

Because of that I changed my intention to a two step solution.

1. Make the forum wide setting a named setting (as you proposed in the PR-discussion) _parent or _top. This would make it possible to provide a dedicated name of a frame/window or the keywords that are relevant for frame handling. Default value would be NULL, keywords (_blank and _self) would get ignored.
2. Add a user setting that activates the value _blank (the other possible keywords makes IMHO no sense in this context).

I don't understand your intention because I don't understand these two cases. Create a variable target_frame. If target_frame == NULL or empty, the target attribute is not necessary and should omitted. In any other case, add the target attribute and use the value defined by target_frame. All cases are considered. There is no need to exclude values nor to define a second variable - please, keep it simple!

/Micha