Created attachment 81739 [details]
Sample Document

Still reproducible with "AOO 4.0.1   – German UI / German locale  [Rev. 1524958 2013-09-20 11:40:29]" on  German WIN7 Home Premium (64bit)", “historic”  4.0  User Profile used for all  predecessor versions:

1. From AOO Start Center open attached sample document 
   > Caret flashes before beginning of text
2. <control+f> for 'Find and Replace' dialog
3. Into 'Find' input line type "general|TAB|absolutely" (or copy / paste
   from here without quotation marks) -> in "More Options" check 
   "Regular Expressions" 
4. [Find] always finds any of the words "general", "tab", "TAB", "absolutely" 
   in text  (as expected)
5. [down-doublearrow] below vertical page scroll slider ('Continue search 
   forward') finds any of the words "general", "tab", "TAB", "absolutely" 
   in text (as expected)
6. [Close] in 'Find and Replace' dialog
   > dialog disappears
7. [down-doublearrow] below vertical page scroll slider ('Continue search 
   forward') finds any of the words "general", "tab", "TAB", "absolutely" 
   in text (as expected)
8. <control+f> to reopen 'Find and Replace' dialog
   Expected: "general|TAB|absolutely" in Find input line 
   Actual: search string with replaced by last found word

Additional info:
(a) that replacing is the normal function, 'Find and Replace' 
    always opens with selected text in Find input line might 
(b) function as per (a) is comfortable for normal search needs, users often
    want to find a selected string at other places in text
(c) function as per (a) is no problem for normal search, because after a 
    search hit the same string what is contents in Find input line is 
    the same as the highlighted string in the text, so input line contents
    will be replaced by an identical text string
(d) but  function as per (a) is not a good idea for find with regular
    expressions, generally user will want top edit the search settings or
    search string after step 8, but if the old search string has become 
    destroyed that will be unnecessary hard
(e) I found this during my investigations for Bug 86411, what might have been
    fixed in between (still some research required)
(f) that never worked better, I already see the complained behavior in 
    OOo 1.1.5
(g) It seems this problem only is relevant for Writer, find functions of
    Calc and Draw are too different.