Line that separates tabs from the page's contents is not painted if tabs are positioned at the bottom or to the right of the control

When tabs are positioned at the bottom of a page control, the horizontal line showing the bottom of the client area is missing (see attached image for an example). Version 5.37 does not have this problem.

Steps to Reproduce:

1. Create a new VCL forms project.

2. Drop a TcxPageControl onto the form.

3. Set the "TabPosition" property of the page control to "tpBottom".

Actual Results:

Tabs are rendered without a horizontal line showing the bottom edge of the tab's client area.

Expected Results:

Tabs are rendered with a horizontal line showing the bottom edge of the tab's client area.