--- mupdf-9999/apps/pdfapp.c
+++ mupdf-9999/apps/pdfapp.c
@@ -858,6 +858,7 @@
 		break;
 
 	case 'b':
+	case '\b': //backspace
 		panto = DONT_PAN;
 		if (app->numberlen > 0)
 			app->pageno -= atoi(app->number);
@@ -866,6 +867,7 @@
 		break;
 
 	case ' ':
+	case 'F':
 		panto = DONT_PAN;
 		if (app->numberlen > 0)
 			app->pageno += atoi(app->number);