I've activated the "show block" option, in french it's in:
Editeur de Texte -> Affichage -> Surligner les blocs
witch I suppose is something like:
Editor -> Display -> show blocks

If I go back to line in the methode/function signature, and if I put my first block bracket after the signature (without going back to line) : the block will not be colored correctly (see capture).

qtcreator_bug_1.png show the bug
qtcreator_bug_2.png and qtcreator_bug_3 show when it doesn't append.