cannot copy/edit page url

[G.Franzl]

Sometimes, at least in private mode wich I commonly use to open links, the url of the page opened cannot be selected/copied/edited - the moment I try to select it with the mouse it vanishes and is replaced by 'search or enter a new url' (which cannot be seleced) - no idea why and when this behaviour occurs, after visiting some other page in another tab and returning to the malfunctioning tab the selecting/copying/editing may work like a charme...

In the described case also the 'send page url by e-mail' option copies no url to the draft e-mail.

Linux: LMDE2, MATE, Midori 0.5.9