designer behaved abnormally...

[sh123]

I right clicked on the designer file & selected change stylesheet option & typed as follows:
QMainWindow
{
background-color:black;
}
the background of form in preview & output showed black after compiling & running.But when i again right clicked on the designer file & selected change stylesheet option & deleted the previously typed code.In the preview it showed as usual(i.e.not black) but after compiling & running it is still showing black background in the output.

[wysota]

Maybe you forgot to save the file in Designer?

[sh123]

no sir,I saved the file

[wysota]

Remove the ui_*.h file created during compilation and rebuild the project.