Fix tooltip showing in wrong locations

[melix99]

Fixes #98

[melix99]

The screen to coords calculation is ok, the real problem was that if the cursor of the mouse is outside of the window, the render function continues to search for words and it picks the words that are on limit in the direction of the cursor. So limiting the search to just when the mouse is hovering the window, it fixes this.

[melix99]

Also, little OT, @BalazsJako it would be great if you can rebase the dev branch to the current master, because dev has a cursor position problem with tabs that has been fixed in master branch (IDK if I can make a rebase in a PR honestly, but I doubt).