For the sake of consistency across all dialogs and window that behave
like dialogs, remove the static line that separates the main part of
the dialog from the standard buttons. This only applies to windows
that have the standard button on the bottom of the frame.
This covers the 3D viewer, CvPcb, common, GerbView and KiCad dialogs.
Calling wxDialog::EndModal() directly from inside the dialog is a
potential bug if the dialog is shown in the modeless or window modal
(quasi-modal). Use the internal button events where possible and
check for the appropriate mode before calling the correct end dialog
function.