Created attachment 74926 [details]
document as descibed above

Problem description: 

FORMATTING: calculated negative numbers are not shown in red colour when reopening a file

Steps to reproduce:
1. New document
2. fill cell a1 with -2, b1 with -1 and c1 with formula =a1+b1 (result: -3)
3. format all three cells as format of number with "negative in red"; all thre cells are shown in red
4. save the file and close libre office
5. open the file again: only cell a1 and b1 are shown in red, c1 is shown black

Current behavior:
see above

Expected behavior:
after reopening the file all three cells should be shown in red
              
Operating System: Windows 7
Version: 4.0.0.3 release
Last worked in: 3.6.5.2 release