Highlighted black spaces?

[luyu]

I’ve noticed strange characters appearing in Writer documents that look like spaces higlighted black. They look just as regular spaces when seen in Page Preview, as opposed to the ones you would higlight manually which would show black in preview too.

They appeared several times, for instance, after copying text from web browser into Writer.

Anyone knows what they are and how to possibly prevent them from showing or is it a bug?

EDIT: Thanks to @manj_k the solution is pinpointed. I looked up some additional info about non-breaking spaces:

• Non-breaking spaces are not broken
  at the end of a line and are entered
  with the Ctrl+Shift+Spacebar shortcut
  keys.

• To prevent two words from being
  separated at the end of a line, hold
  down the Ctrl key and the Shift key
  when you type a space between the
  words. In Calc, you cannot insert
  non-breaking
  spaces.

• Non-breaking spaces are not used for
  hyphenation and are not expanded if
  the text is
  justified.

It’s Unicode value is U+00A0 and it can be searched for in a document using \x00A0 provided regular expresions are enabled.

[manj_k]

Non-breaking spaces (formatting marks)?

You might toggle View → Field Shadings (Ctrl+F8).

[luyu]

That’s it. Thanks!