The situations in OOo-dev300-m21_en as follows：
1.find（all）〠replace( all) are greyed-out till something is written 
in 'serach for' box ï¼›
2.when 'regular expressions'checkbox is not selected,'.*','.?'and '^$'have the 
same results-pop-up"search key not found" dialogueï¼›
3.when the 'regular expressions'checkbox is selected,'.*' and '.?'will search 
non-void cells,while '^$' pop-up"search key not found" dialogue.
BTW,OOo_calc can't search only in selected cells area(MS_Excel works),
that is ,calc can only search in the whole "worksheet" or "workbook", which 
may be the essential matter. (my OS is Windows Xp)
Frankly.

Since Cheng Huai Lei (chl207) has confirmed this, and I also confirm this behaviour in DEV300_m21 
Vietnamese (OSX Intel, 10.5.4), I am confirming this issue.

The inability to search for a null string (especially via regex) is definitely a defect. The interface is also 
unintuitive in the case of a null string. Optimally, the Help and the interface should be amended to 
handle the null-string search situation.

Hi,

the search term ^$ should find an empty paragraph, but you do not have any
paragraph in a spreadsheet. So this seems to be a misuse of a reg. expression
for Writer in Calc.

Eike, what do you think about it ?

Frank

The problem is more that an empty cell has _no_ content, not even an empty
paragraph, and cells without content aren't searched. This could be enhanced to
match empty cells for the '^$' expression as a special case. Including empty
cells for an expression of '.*' or '.?' IMHO wouldn't make much sense as it
would match every cell then.

@oopla: to have the online help mention that only non-empty cells are searched,
please file a separate issue for the documentation project.

Thanks
  Eike

Not a RE misuse, IMHO: calc should handle it properly.
OOo seems to use ERE; '^$' matches start-of-string,end-of-string, where
start-of-string is the position at the very beginning of the string and 
end-of-string the very last one; from OOo help seems though ERE used are
'no-multi-line': {start,end}-of-string match the {start,end} position of
a single line, ie the positions {after,before} end-of-line (aka 'paragraph' 
in OOo?), or the very {start,end} if there's no '\n'.

So if Calc allows for multi-line (ie '\n' is legal) cell content:
 - '^$' would match any 0-length line.
 - likewise, '.*' would match every line while '.+' would match 
   non-void lines only, since in no-multi-line ERE '.' doesn't 
   match '\n'.
 - a single '\n' may be collapsed to a void cell, so it'd avoid the
   existance of such strange single-but-void paragraph.
Else (no multi-line cell content, no '\n' allowed), '^$' would never
match and '.*', '.+' would practically be equivalent, _if_ void cells 
are removed from (string) search space.

And I do agree that it sounds reasonable to skip void cells: having no
searchable content, they should not be in RE/filter (string) search space
(besides, removing void cells from search space likely have huge impact 
on performance and resources usage).

So it's a doc/help problem, but point above must first be clarified: 
is '\n' legal in cell content, ie can cell content be multi-line?

thx
-- paolo 

This issue is related to (at least) issues 90658 and 89816. Calc's handling of null values is non-standard. 
Should we combine the info here?

No, this issue is not related to issue 90658 nor issue 89816. This issue here is
about considering empty cells when searching for an empty string respectively
the empty paragraph regular expression. Issue 90658 is about a formula's error
result confusing the list of available values in AutoFilter. Issue 89816 is
about the automatic selection of the data area if none was selected.

Maybe duplicate of this one : http://qa.openoffice.org/issues/show_bug.cgi?id=44688

Indeed, it's a dupe.

@oopla: yes, cell content can be multi-line, use Ctrl+Enter to insert a
linefeed, and will be found when using the \n regex.


*** This issue has been marked as a duplicate of 44688 ***

Closing dup.