Hello Community,
I spot a different behavior of a Link functionality (CRTL+K).
In the most of the pages it behaves in an expected way - the Insert Link popup is displayed and it is possible add needed link (see following insert_link_01.png)
In some pages when I want to Insert a link different pop-up window is displayed and I'm able to link only pages (see following insert_link_02.png).

What is causing this difference. I expect that behavior of the insert functionality should be same. It brings problems when I cannot link e.g. files attached to the page.
Any response is welcome.
Vlada