Bug confirmed with LO 3.5.0 - 3.5.2 running on Win 7 and XP.

Steps to reproduce:
1. Start and save 2 new Calc files (A.ods, B.ods)
2. Enter a data into cell A1 of A.ods and copy it
3. Select cell A1 of B.ods and go to "Edit" -> "Paste Special" ->
   Enable "Link" check box and press "OK" OR select "DDE Link" from
   "Paste" icon

LO 3.5 does not insert a DDE link but only a regular file link and
does not refresh link automatically when changes are made to A.ods.
It has to be refreshed manually which defeats the whole purpose of
DDE link.(It cannot be set to "Auto" via "Edit" -> "Link" as it is
greyed out.)

Notice the formula on the input line is of a regular file link;
{='file:///C:/Users/user name/Desktop/A.ods'#$Sheet1.A1}

When it should look like this;
{=DDE("soffice","C:/Users/user name/Desktop/A.ods","Sheet1.A1")}

DDE links created with earlier versions are still there when opened
with 3.5.x. Also, manually entering the DDE link formula works with
3.5.x as well.(It is too time consuming, not really a work around.)

Therefore, the DDE link itself is still there. However, the function
to insert it via "Paste" is not working properly.

When pasting copied data as a link, be it a DDE link or allow user
to choose whether to update the link manually or automatically.