LCL: Application.HideHint: clear HintControl and HintRect to allow showing another hint

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45366 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: messages: hint: shorter reshow

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45367 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: messages: update scrollbar on resize

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@45368 4005530d-fff6-0310-9dd1-cebe43e6787f