Writer focus issue (?)

In Ubuntu 18.04 with Gnome-shell when opening new or existing files in LO Writer I have to click in the text field with the mouse to be able to type or to use keyboard shortcuts to work with the text. For instance, I want to search for text in a Writer file, I open it and when I press Ctrl+F nothing happens until I click somewhere in the text. Similarly, I cannot type in new files until I put the cursor on the file with the mouse. How do I get rid of this annoyance?