Small cosmetics for the preference panel

* Prevent the scrollview from jumping vertically when selecting a service
* Glue the services view to the top

src/preferences/network/NetworkWindow.cpp

@@ -126,7 +126,7 @@ NetworkWindow::NetworkWindow()
 
 	BScrollView* scrollView = new BScrollView("ScrollView", fListView,
 		0, false, true);
-	scrollView->SetExplicitMinSize(BSize(B_SIZE_UNSET, 42));
+	scrollView->SetExplicitMaxSize(BSize(B_SIZE_UNLIMITED, B_SIZE_UNSET));
 
 	fAddOnShellView = new BView("add-on shell", 0,
 		new BGroupLayout(B_VERTICAL));

src/preferences/network/ServiceView.cpp

@@ -50,6 +50,7 @@ ServiceView::ServiceView(const char* name, const char* executable,
 	BLayoutBuilder::Group<>(this, B_VERTICAL)
 		.Add(titleView)
 		.Add(descriptionView)
+		.AddGlue()
 		.AddGroup(B_HORIZONTAL)
 			.AddGlue()
 			.Add(fEnableButton);