diff -uNdr wavelet-denoise-0.3.1_orig/src/interface.c wavelet-denoise-0.3.1_new/src/interface.c
--- wavelet-denoise-0.3.1_orig/src/interface.c	2020-01-29 13:51:57.898428612 +0300
+++ wavelet-denoise-0.3.1_new/src/interface.c	2020-01-29 14:02:25.806034526 +0300
@@ -16,8 +16,34 @@
 #include "plugin.h"
 #include "interface.h"
 
+/* colour mode frame */
+GtkWidget *fr_mode, *mode_radio[3], *mode_vbox;
+GSList *mode_list;
+
+/* preview select frame */
+GtkWidget *fr_preview, *preview_radio[3], *preview_vbox, *preview_check;
+GSList *preview_list;
+
+/* channel select frame */
+GtkWidget *fr_channel, *channel_radio[4], *channel_vbox;
+GSList *channel_list;
+
+/* threshold frame */
+GtkWidget *fr_threshold, *thr_label[2], *thr_spin[2];
+GtkWidget *thr_hbox[2], *thr_vbox, *thr_scale[2];
+GtkObject *thr_adj[2];
+
+/* reset buttons */
+GtkWidget *reset_button[2], *reset_hbox, *reset_align, *reset_button_icon[2];
+
+/* dialog */
+GtkWidget *dialog, *dialog_hbox, *dialog_vbox, *frame_hbox, *dialog_aspect;
+GtkWidget *preview, *preview_reset, *preview_hbox, *preview_reset_icon;
+
 GtkWidget **radios_labels[] = { channel_radio, thr_label };
 
+char **names;
+
 gboolean
 user_interface (GimpDrawable * drawable)
 {
diff -uNdr wavelet-denoise-0.3.1_orig/src/interface.h wavelet-denoise-0.3.1_new/src/interface.h
--- wavelet-denoise-0.3.1_orig/src/interface.h	2020-01-29 13:51:57.900428541 +0300
+++ wavelet-denoise-0.3.1_new/src/interface.h	2020-01-29 13:57:27.305678240 +0300
@@ -14,29 +14,29 @@
  */
 
 /* colour mode frame */
-GtkWidget *fr_mode, *mode_radio[3], *mode_vbox;
-GSList *mode_list;
+extern GtkWidget *fr_mode, *mode_radio[3], *mode_vbox;
+extern GSList *mode_list;
 
 /* preview select frame */
-GtkWidget *fr_preview, *preview_radio[3], *preview_vbox, *preview_check;
-GSList *preview_list;
+extern GtkWidget *fr_preview, *preview_radio[3], *preview_vbox, *preview_check;
+extern GSList *preview_list;
 
 /* channel select frame */
-GtkWidget *fr_channel, *channel_radio[4], *channel_vbox;
-GSList *channel_list;
+extern GtkWidget *fr_channel, *channel_radio[4], *channel_vbox;
+extern GSList *channel_list;
 
 /* threshold frame */
-GtkWidget *fr_threshold, *thr_label[2], *thr_spin[2];
-GtkWidget *thr_hbox[2], *thr_vbox, *thr_scale[2];
-GtkObject *thr_adj[2];
+extern GtkWidget *fr_threshold, *thr_label[2], *thr_spin[2];
+extern GtkWidget *thr_hbox[2], *thr_vbox, *thr_scale[2];
+extern GtkObject *thr_adj[2];
 
 /* reset buttons */
-GtkWidget *reset_button[2], *reset_hbox, *reset_align, *reset_button_icon[2];
+extern GtkWidget *reset_button[2], *reset_hbox, *reset_align, *reset_button_icon[2];
 
 /* dialog */
-GtkWidget *dialog, *dialog_hbox, *dialog_vbox, *frame_hbox, *dialog_aspect;
-GtkWidget *preview, *preview_reset, *preview_hbox, *preview_reset_icon;
+extern GtkWidget *dialog, *dialog_hbox, *dialog_vbox, *frame_hbox, *dialog_aspect;
+extern GtkWidget *preview, *preview_reset, *preview_hbox, *preview_reset_icon;
 
 extern GtkWidget **radios_labels[];
 
-char **names;
+extern char **names;
diff -uNdr wavelet-denoise-0.3.1_orig/src/plugin.c wavelet-denoise-0.3.1_new/src/plugin.c
--- wavelet-denoise-0.3.1_orig/src/plugin.c	2020-01-29 13:51:57.898428612 +0300
+++ wavelet-denoise-0.3.1_new/src/plugin.c	2020-01-29 13:56:00.937759092 +0300
@@ -15,6 +15,11 @@
 
 #include "plugin.h"
 
+float *fimg[4];
+float *buffer[3];
+gint channels;
+GTimer *timer;
+
 GimpPlugInInfo PLUG_IN_INFO = { NULL, NULL, query, run };
 
 wavelet_settings settings = {
diff -uNdr wavelet-denoise-0.3.1_orig/src/plugin.h wavelet-denoise-0.3.1_new/src/plugin.h
--- wavelet-denoise-0.3.1_orig/src/plugin.h	2020-01-29 13:51:57.899428576 +0300
+++ wavelet-denoise-0.3.1_new/src/plugin.h	2020-01-29 13:56:02.038719819 +0300
@@ -93,10 +93,10 @@
 extern char *names_gray[];
 extern char *names_lab[];
 
-float *fimg[4];
-float *buffer[3];
-gint channels;
+extern float *fimg[4];
+extern float *buffer[3];
+extern gint channels;
 
-GTimer *timer;
+extern GTimer *timer;
 
 #endif /* __PLUGIN_H__ */