[Steps]
1. Create a Impress doc
2. Move cursor onto one style in "Layouts" bar, such as "Title, Text".
Right-click -> "Insert Slide"

[Result]
The inserted slide is still blank, no layout applied.
(Strictly speaking, the inserted slide by "right-click -> Insert Slide" will
copy the style of the slide which just before the inserted one.)

[Expected]
The layout can be applied via Right-click -> "Insert Slide" from layout bar.