[Lazarus] fixes_1_8 - DBLookupComboBox broken

[Gabor Boros]

Hi All,

I have a Linux-Qt application and if compile with fixes_1_8 rev 56990 or 
later the DBLookupComboBox not working as before. Can drop down it and 
select from the items with the mouse but the selection not showed. The 
problem not appears with rev 56987.

Gabor