Scroll Area Widget Contents not visible as sender/receiver in form editor

In form editor (for *.ui files) when we add Scroll Area it gets a child widget with name "scrollAreaWidgetContents...". The name of this widget is not available as a sender/receiver, i.e. we can't drag a connection in form view and also we are unable to select it from a list in signal/slot editor. My very inconvenient workaround is to add <connection> section by hand in ui file.