diff --git a/textscreen/txt_fileselect.c b/textscreen/txt_fileselect.c
index 42b6f42d..21016b79 100644
--- a/textscreen/txt_fileselect.c
+++ b/textscreen/txt_fileselect.c
@@ -808,7 +808,7 @@ static void InputBoxChanged(TXT_UNCAST_ARG(widget), TXT_UNCAST_ARG(fileselect))
 }
 
 txt_fileselect_t *TXT_NewFileSelector(char **variable, int size,
-                                      char *prompt, const char **extensions)
+                                      const char *prompt, const char **extensions)
 {
     txt_fileselect_t *fileselect;
 
diff --git a/textscreen/txt_fileselect.h b/textscreen/txt_fileselect.h
index 10ed84c1..fe5fac79 100644
--- a/textscreen/txt_fileselect.h
+++ b/textscreen/txt_fileselect.h
@@ -66,7 +66,7 @@ char *TXT_SelectFile(const char *prompt, const char **extensions);
  */
 
 txt_fileselect_t *TXT_NewFileSelector(char **variable, int size,
-                                      char *prompt, const char **extensions);
+                                      const char *prompt, const char **extensions);
 
 /**
  * Special value to use for 'extensions' that selects a directory