Fix tdmtheme crash

This resolves Bug 1544

src/tdmtheme.cpp

@@ -268,16 +268,22 @@ void TDMThemeWidget::insertTheme( const TQString &_theme )
 
 void TDMThemeWidget::updateInfoView( ThemeData *theme )
 {
-	info->setText(
-		((theme->copyright.length() > 0) ?
-			i18n("<qt><strong>Copyright:</strong> %1<br/></qt>",
-				theme->copyright) : "") +
-		((theme->description.length() > 0) ?
-			i18n("<qt><strong>Description:</strong> %1</qt>",
-				theme->description) : "") );
-	preview->setPixmap( theme->path + '/' + theme->screenShot );
-	preview->setText( theme->screenShot.isEmpty() ?
-		"Screenshot not available" : TQString() );
+	if(theme) {
+		info->setText(
+			((theme->copyright.length() > 0) ?
+				i18n("<qt><strong>Copyright:</strong> %1<br/></qt>",
+					theme->copyright) : "") +
+			((theme->description.length() > 0) ?
+				i18n("<qt><strong>Description:</strong> %1</qt>",
+					theme->description) : "") );
+		preview->setPixmap( theme->path + '/' + theme->screenShot );
+		preview->setText( theme->screenShot.isEmpty() ?
+			i18n("Screenshot not available") : TQString() );
+	} else {
+		info->setText(i18n("No theme selected."));
+		preview->setPixmap(NULL);
+		preview->setText(i18n("Screenshot not available"));
+	}
 }
 
 void TDMThemeWidget::installNewTheme()