Can reproduce it in DEV300m49 on WinXP

firstly,create a new writer or Spreadsheet doc like t.odt or s.ods, then rename
t.odt as t.odp or t.odg, or rename s.ods as s.odp or s.odg, open t.odp or t.odg,
s.odp or s.odg with OOo
-> t.odp or t.odg,s.odp or s.odg is not opened, but create a new presentation or
drawing file

Secondly, create a new Presentation doc like p.odp, then rename it as p.odg,
then open p.odg with OOo
-> p.odg is opened with drawing, file content is visible, but add new text box
and title box

Thirdly, create a new drawing doc like g.odg, then rename it as g.odp, then open
g.odp with OOo
-> g.odp is opened with presentation, file content is visible

Expectation
Opening file works well

Note, at firstly, open s.odp or s.odg failed but create a new presentation or
drawing file, and OOo is no response

Regards
Li Meiying