Fix layout of error dialog TLW.

Thanks Leland for the suggested fix.
Works OK on Linux, please test on other platforms.

src/widgets/ErrorDialog.cpp

@@ -102,7 +102,7 @@ ErrorDialog::ErrorDialog(
    S.EndVerticalLay();
 
    Layout();
-   Fit();
+   GetSizer()->Fit(this);
    SetMinSize(GetSize());
    Center();