From: https://sourceforge.net/p/gmtp/discussion/bugs/thread/7b11b950bd

--- a/src/interface.c
+++ b/src/interface.c
@@ -40,8 +40,8 @@
 #include "formatdevice.h"
 #include "progress.h"
 
-void setupFileList();
-GtkTreeViewColumn *setupFolderList();
+void setupFileList(GtkTreeView *treeviewFiles);
+GtkTreeViewColumn *setupFolderList(GtkTreeView *treeviewFolders);
 void __fileRemove(GtkTreeRowReference *Row);
 void __fileDownload(GtkTreeRowReference *Row);
 void __folderRemove(GtkTreeRowReference *Row);
@@ -713,7 +713,7 @@ GtkWidget* create_windowMain(void) {
     gtk_tree_selection_set_mode(folderSelection, GTK_SELECTION_SINGLE);
 
     folderList = gtk_tree_store_new(NUM_FOL_COLUMNS, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_UINT, GDK_TYPE_PIXBUF);
-    folderColumn = setupFolderList(treeviewFolders);
+    folderColumn = setupFolderList(GTK_TREE_VIEW(treeviewFolders));
 
     folderListModel = gtk_tree_model_sort_new_with_model(GTK_TREE_MODEL(folderList));
     gtk_tree_sortable_set_sort_column_id(GTK_TREE_SORTABLE(folderListModel),
@@ -741,7 +741,7 @@ GtkWidget* create_windowMain(void) {
             G_TYPE_UINT, G_TYPE_BOOLEAN, G_TYPE_UINT64, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_UINT, G_TYPE_STRING,
             G_TYPE_STRING, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_STRING, G_TYPE_UINT, GDK_TYPE_PIXBUF,
             G_TYPE_STRING);
-    setupFileList(treeviewFiles);
+    setupFileList(GTK_TREE_VIEW(treeviewFiles));
 
     fileListModel = gtk_tree_model_sort_new_with_model(GTK_TREE_MODEL(fileList));
     gtk_tree_sortable_set_sort_column_id(GTK_TREE_SORTABLE(fileListModel),