Fixed leaking formatBlockSelectItem variable.
Fixed leaking formatBlockSelectItem variable.

Variable formatBlockSelectItem (with header html input) was leaked and if variable is set by first html editor (with enableFormatBlocks=True), then second html editor (with enableFormatBlocks=False) in the same page attach it self to this select input. Then select input change is proped to both editors

ateodorescu/mzExt,dbirchak/mzExt,ateodorescu/mzExt