If I want to rename a variable I can put the cursor somewhere in the variable name and then, either press Ctrl+R or right click and choose Rename from the menu.
But if I first double click the variable name so it is highlighted, then I can't press Ctrl+R, nothing happens. But right click and choose Rename from the menu works of course.
If I right click on the highlighted variable name and choose Rename to open the rename dialog, and then cancel the rename dialog, now the Ctrl+R pressing works!
As stated in the subject, I'm using version 5.1.0 build 5206. This works as it should in version 5.1.0 build 5134