Bogus spaces inserted when pasting to VIM

[Tim Dijkstra <newsuser@famdijkstra.org>]

Hi,

I have this annoying problem when using VIM. If I select in one instance of VIM (using the mouse) some text that starts with some spaces, like:

local_folder_delivery:
  driver = appendfile
  group = mail
  mode = 0660
  mode_fail_narrower = false
  envelope_to_add = true
  directory = ${home}/Maildir/.$h_X-gotmail-folder
  maildir_format = true

And than paste (clicking the middle button) in another instance, it inserts spaces at the beginning of the lines, which results in:

local_folder_delivery:
  driver = appendfile
    group = mail
      mode = 0660
        mode_fail_narrower = false
          envelope_to_add = true
            directory = ${home}/Maildir/.$h_X-gotmail-folder
              maildir_format = true
              
Does anybody have seen this before and, more importantly, does anybody know a fix for this? 

grts Tim