Action column in Visitor Log shows pages not on my site

I am trying to understand the Actions column in the Visitor Log.
In most cases it shows pages visited on my site, and if user clicked one of the links to another site, then the address that was clicked.
However, in the attached image http://s6.postimg.org/4z0jll61d/Question_To_Piwik.jpg the third row has two actions and both URLs are not on my site but rather on stackoverflow.com. The bottom fourth row has the first action not on my site (java-forums.org) while the second action is on my site.
My site is baruchyoussin.com.

What is the meaning of these two rows with initial actions on other sites?

Reviewing the server logs, I understood this issue.

This actions are visitor clicking one of the outside links on my page. This is indicated by a little symbol that precedes the URL of the action.

There is one visit that has just two actions, clicking two links but not viewing any pages on my site on which these links may be clicked.

Visitor profile for this visit indicates that this is the second visit of the same visitor, the first having been 10 hours earlier and on the first visit there was one page opened that included both links clicked.

Apparently this visitor has kept my page opened for 10 hours and then clicked two links on it.

The second puzzling visit has two actions, the first one following an outside link and the second one opening a page on my site.

In this case Visitor profile indicated that this visitor visited 1.5 hours earlier and opened the same page on that visit.
On the second visit there were two actions, the first one following an outside link and the second one was reloading the same page.
The page was probably kept open and the link was followed on it before the page was reloaded.