QmlDesigner.PropertyEditor: some adjustment to ComboBox style

Change-Id: I52a80941e343ad9ad3cca7bc0bcdec8fe0a90156
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner.PropertyEditor: adjust TabView style

Styling the TabView in css is problematic and we want to keep
the style in sync. So we use the old style here.

Change-Id: I57ed39a03b4b4c59e9a996ca4e14d4d9fe9dfeb2
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: adjustment of Section(View)

Adjusting the item library and property editor,
so they follow the same style for sections.

Change-Id: I79d3560acff3b126056cf55b81fd21a531f9594c
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: adjusting scrollbar

Going for a simpler and cleaner design that works well with css.
The old one looked broken.

Change-Id: I034febcd2b9d9f395945ebad153934990c1e3d81
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesiger.PropertyEditor: adjust background color

Change-Id: I403c37f2cda84980dfe441746f3c5bed7258a4ca
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>