When using favourite folder view on a small netbook screen I want to disable folder list by dragging the splitter to the bottom - like I can do with the calendar folder view in korganizer.
But in KMail2 the splitter can not be zero. I am forced to watch the folder list. This is a regression to kmail1 in KDE3 :-)

Reproducible: Always

Steps to Reproduce:
1. activate favorite folder icon view
2. drag spltter between favorite folder list and std folder list down to bottom

Actual Results:  
 a small area of the std folder list stays visible

Expected Results:  
only the small splitter handle stays visible like in korganizer calendar folder view.
When corrected it should be checked if the splitter position is saved when restarting kmail/kontact

kdepim/kmail/kmmainwidget.cpp shows at line ~680:

if ( mFavoriteCollectionsView ) {
    mFolderViewSplitter = new QSplitter( Qt::Vertical );
    mFolderViewSplitter->setOpaqueResize( opaqueResize );
    mFolderViewSplitter->setChildrenCollapsible( false );
    mFolderViewSplitter->addWidget( mFavoriteCollectionsView );
    mFavoriteCollectionsView->setParent( mFolderViewSplitter );
    mFolderViewSplitter->addWidget( mSearchAndTree );
    folderTreeWidget = mFolderViewSplitter;
  }

setChildrenCollapsible( false ) disables collapsing of the children widget.

kmail --version
Qt: 4.8.1
KDE: 4.8.4 (4.8.4)
KMail: 4.8.4