fix boxsel misbehaviour when pasting with middle click.
fix boxsel misbehaviour when pasting with middle click.

When in terminology, user selects some text with boxselection (shift +
click/drag) and pastes in the same window with middle click.
The box selection then transforms into normal. Now it's fixed.

bssb/terminology,ihorlaitan/terminology,ihorlaitan/terminology,bssb/terminology,ihorlaitan/terminology,godfath3r/terminology,godfath3r/terminology,godfath3r/terminology,bssb/terminology