ITextMark: Fix crash with invisible marks
ITextMark: Fix crash with invisible marks

Task-number: QTCREATORBUG-7884

Change-Id: I40525b2d35e7c5a806d4047bd5b503937798da0b
Reviewed-by: Eike Ziller <c142da16c73a95a82d35191bcc55b22835617128@digia.com>

farseerri/git_code,richardmg/qtcreator,danimo/qt-creator,xianian/qt-creator,maui-packages/qt-creator,colede/qtcreator,amyvmiwei/qt-creator,xianian/qt-creator,Distrotech/qtcreator,maui-packages/qt-creator,omniacreator/qtcreator,malikcjm/qtcreator,AltarBeastiful/qt-creator,danimo/qt-creator,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,farseerri/git_code,xianian/qt-creator,kuba1/qtcreator,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,AltarBeastiful/qt-creator,omniacreator/qtcreator,colede/qtcreator,farseerri/git_code,martyone/sailfish-qtcreator,maui-packages/qt-creator,kuba1/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,AltarBeastiful/qt-creator,darksylinc/qt-creator,duythanhphan/qt-creator,maui-packages/qt-creator,danimo/qt-creator,colede/qtcreator,darksylinc/qt-creator,omniacreator/qtcreator,malikcjm/qtcreator,amyvmiwei/qt-creator,AltarBeastiful/qt-creator,duythanhphan/qt-creator,malikcjm/qtcreator,farseerri/git_code,maui-packages/qt-creator,duythanhphan/qt-creator,amyvmiwei/qt-creator,richardmg/qtcreator,kuba1/qtcreator,richardmg/qtcreator,kuba1/qtcreator,omniacreator/qtcreator,malikcjm/qtcreator,kuba1/qtcreator,maui-packages/qt-creator,duythanhphan/qt-creator,colede/qtcreator,malikcjm/qtcreator,AltarBeastiful/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,danimo/qt-creator,darksylinc/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,danimo/qt-creator,duythanhphan/qt-creator,malikcjm/qtcreator,richardmg/qtcreator,duythanhphan/qt-creator,martyone/sailfish-qtcreator,darksylinc/qt-creator,richardmg/qtcreator,danimo/qt-creator,richardmg/qtcreator,darksylinc/qt-creator,amyvmiwei/qt-creator,colede/qtcreator,colede/qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,farseerri/git_code,farseerri/git_code,danimo/qt-creator,kuba1/qtcreator,richardmg/qtcreator,kuba1/qtcreator,darksylinc/qt-creator,darksylinc/qt-creator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,colede/qtcreator,amyvmiwei/qt-creator,duythanhphan/qt-creator,darksylinc/qt-creator,amyvmiwei/qt-creator,malikcjm/qtcreator,xianian/qt-creator,omniacreator/qtcreator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,omniacreator/qtcreator,maui-packages/qt-creator,omniacreator/qtcreator,Distrotech/qtcreator,Distrotech/qtcreator