[OSM-newbies] how to scroll over the map in JOSM?

[mariner]

John McKerrell wrote:
> On 14 Mar 2008, at 07:23, mariner wrote:
>
>   
>>> Move the mouse while holding the right mouse-button pressed, this  
>>> will move
>>> the viewport.
>>>
>>>
>>>       
>> Thank you... That is the thing I was looking for.
>>     
>
> Worth pointing out that you can also hold ctrl down while pressing  
> the cursor keys too (good for mac users).
>
> John
>   
that sometimes caused problems.  it didn't scroll but selected an other
icon of the properties on the right side. i think the focus were not on
the map.

how can i set the focus on the main window?