diff --git a/src/sound.c b/src/sound.c
index 99c9868..7b4d984 100644
--- a/src/sound.c
+++ b/src/sound.c
@@ -48,23 +48,23 @@
     soundcb_T *soundcb;
 
     if (arg->v_type == VAR_UNKNOWN)
-	return NULL;
+        return NULL;
     callback = get_callback(arg);
     if (callback.cb_name == NULL)
-	return NULL;
+        return NULL;
 
     soundcb = ALLOC_ONE(soundcb_T);
     if (soundcb == NULL)
     {
-	free_callback(&callback);
-	return NULL;
+        free_callback(&callback);
+        return NULL;
     }
 
     soundcb->snd_next = first_callback;
     first_callback = soundcb;
     set_callback(&soundcb->snd_callback, &callback);
     if (callback.cb_free_name)
-	vim_free(callback.cb_name);
+        vim_free(callback.cb_name);
     return soundcb;
 }
 
@@ -97,16 +97,16 @@
     soundcb_T *prev = NULL;
 
     for (p = first_callback; p != NULL; prev = p, p = p->snd_next)
-	if (p == soundcb)
-	{
-	    if (prev == NULL)
-		first_callback = p->snd_next;
-	    else
-		prev->snd_next = p->snd_next;
-	    free_callback(&p->snd_callback);
-	    vim_free(p);
-	    break;
-	}
+        if (p == soundcb)
+        {
+            if (prev == NULL)
+                first_callback = p->snd_next;
+            else
+                prev->snd_next = p->snd_next;
+            free_callback(&p->snd_callback);
+            vim_free(p);
+            break;
+        }
 }
 
 # if defined(HAVE_CANBERRA) || defined(PROTO)
@@ -139,24 +139,24 @@
  */
 static void
 sound_callback(ca_context *c UNUSED,
-	       uint32_t id,
-	       int error_code,
-	       void *userdata)
+               uint32_t id,
+               int error_code,
+               void *userdata)
 {
     soundcb_T *soundcb = (soundcb_T *)userdata;
     soundcb_queue_T *scb;
 
     scb = ALLOC_ONE(soundcb_queue_T);
     if (scb == NULL)
-	return;
+        return;
     scb->scb_next = callback_queue;
     callback_queue = scb;
     scb->scb_id = id;
     scb->scb_result = error_code == CA_SUCCESS ? 0
-		      : error_code == CA_ERROR_CANCELED ||
-			      error_code == CA_ERROR_DESTROYED
-			  ? 1
-			  : 2;
+                      : error_code == CA_ERROR_CANCELED ||
+                              error_code == CA_ERROR_DESTROYED
+                          ? 1
+                          : 2;
     scb->scb_callback = soundcb;
 }
 
@@ -179,13 +179,13 @@
 
     while (callback_queue != NULL)
     {
-	scb = callback_queue;
-	callback_queue = scb->scb_next;
+        scb = callback_queue;
+        callback_queue = scb->scb_next;
 
-	call_sound_callback(scb->scb_callback, scb->scb_id, scb->scb_result);
+        call_sound_callback(scb->scb_callback, scb->scb_id, scb->scb_result);
 
-	delete_sound_callback(scb->scb_callback);
-	vim_free(scb);
+        delete_sound_callback(scb->scb_callback);
+        vim_free(scb);
     }
     redraw_after_callback(TRUE, FALSE);
 }
@@ -194,12 +194,12 @@
 sound_play_common(typval_T *argvars, typval_T *rettv, int playfile)
 {
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     if (context == NULL)
-	ca_context_create(&context);
+        ca_context_create(&context);
     if (context == NULL)
-	return;
+        return;
 
     soundcb_T *soundcb = get_sound_callback(&argvars[1]);
     int res = CA_ERROR_INVALID;
@@ -207,34 +207,34 @@
     ++sound_id;
     if (soundcb == NULL)
     {
-	res = ca_context_play(context, sound_id,
-			      playfile ? CA_PROP_MEDIA_FILENAME
-				       : CA_PROP_EVENT_ID,
-			      tv_get_string(&argvars[0]),
-			      CA_PROP_CANBERRA_CACHE_CONTROL, "volatile", NULL);
+        res = ca_context_play(context, sound_id,
+                              playfile ? CA_PROP_MEDIA_FILENAME
+                                       : CA_PROP_EVENT_ID,
+                              tv_get_string(&argvars[0]),
+                              CA_PROP_CANBERRA_CACHE_CONTROL, "volatile", NULL);
     }
     else
     {
-	static ca_proplist *proplist = NULL;
+        static ca_proplist *proplist = NULL;
 
-	ca_proplist_create(&proplist);
-	if (proplist != NULL)
-	{
-	    if (playfile)
-		ca_proplist_sets(proplist, CA_PROP_MEDIA_FILENAME,
-				 (char *)tv_get_string(&argvars[0]));
-	    else
-		ca_proplist_sets(proplist, CA_PROP_EVENT_ID,
-				 (char *)tv_get_string(&argvars[0]));
-	    ca_proplist_sets(proplist, CA_PROP_CANBERRA_CACHE_CONTROL,
-			     "volatile");
-	    res = ca_context_play_full(context, sound_id, proplist,
-				       sound_callback, soundcb);
-	    if (res != CA_SUCCESS)
-		delete_sound_callback(soundcb);
+        ca_proplist_create(&proplist);
+        if (proplist != NULL)
+        {
+            if (playfile)
+                ca_proplist_sets(proplist, CA_PROP_MEDIA_FILENAME,
+                                 (char *)tv_get_string(&argvars[0]));
+            else
+                ca_proplist_sets(proplist, CA_PROP_EVENT_ID,
+                                 (char *)tv_get_string(&argvars[0]));
+            ca_proplist_sets(proplist, CA_PROP_CANBERRA_CACHE_CONTROL,
+                             "volatile");
+            res = ca_context_play_full(context, sound_id, proplist,
+                                       sound_callback, soundcb);
+            if (res != CA_SUCCESS)
+                delete_sound_callback(soundcb);
 
-	    ca_proplist_destroy(proplist);
-	}
+            ca_proplist_destroy(proplist);
+        }
     }
     rettv->vval.v_number = res == CA_SUCCESS ? sound_id : 0;
 }
@@ -261,10 +261,10 @@
 f_sound_stop(typval_T *argvars, typval_T *rettv UNUSED)
 {
     if (in_vim9script() && check_for_number_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     if (context != NULL)
-	ca_context_cancel(context, tv_get_number(&argvars[0]));
+        ca_context_cancel(context, tv_get_number(&argvars[0]));
 }
 
 /*
@@ -274,7 +274,7 @@
 f_sound_clear(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
 {
     if (context == NULL)
-	return;
+        return;
     ca_context_destroy(context);
     context = NULL;
 }
@@ -286,17 +286,17 @@
     soundcb_queue_T *scb;
 
     if (context != NULL)
-	ca_context_destroy(context);
+        ca_context_destroy(context);
 
     while (first_callback != NULL)
-	delete_sound_callback(first_callback);
+        delete_sound_callback(first_callback);
 
     while (callback_queue != NULL)
     {
-	scb = callback_queue;
-	callback_queue = scb->scb_next;
-	delete_sound_callback(scb->scb_callback);
-	vim_free(scb);
+        scb = callback_queue;
+        callback_queue = scb->scb_next;
+        delete_sound_callback(scb->scb_callback);
+        vim_free(scb);
     }
 }
 #  endif
@@ -316,25 +316,25 @@
 
     switch (message)
     {
-	case MM_MCINOTIFY:
-	    for (p = first_callback; p != NULL; p = p->snd_next)
-		if (p->snd_device_id == (MCIDEVICEID)lParam)
-		{
-		    char buf[32];
+        case MM_MCINOTIFY:
+            for (p = first_callback; p != NULL; p = p->snd_next)
+                if (p->snd_device_id == (MCIDEVICEID)lParam)
+                {
+                    char buf[32];
 
-		    vim_snprintf(buf, sizeof(buf), "close sound%06ld",
-				 p->snd_id);
-		    mciSendStringA(buf, NULL, 0, 0);
+                    vim_snprintf(buf, sizeof(buf), "close sound%06ld",
+                                 p->snd_id);
+                    mciSendStringA(buf, NULL, 0, 0);
 
-		    long result = wParam == MCI_NOTIFY_SUCCESSFUL ? 0
-				  : wParam == MCI_NOTIFY_ABORTED  ? 1
-								  : 2;
-		    call_sound_callback(p, p->snd_id, result);
+                    long result = wParam == MCI_NOTIFY_SUCCESSFUL ? 0
+                                  : wParam == MCI_NOTIFY_ABORTED  ? 1
+                                                                  : 2;
+                    call_sound_callback(p, p->snd_id, result);
 
-		    delete_sound_callback(p);
-		    redraw_after_callback(TRUE, FALSE);
-		}
-	    break;
+                    delete_sound_callback(p);
+                    redraw_after_callback(TRUE, FALSE);
+                }
+            break;
     }
 
     return DefWindowProc(hwnd, message, wParam, lParam);
@@ -345,12 +345,12 @@
 {
     if (g_hWndSound == NULL)
     {
-	LPCSTR clazz = "VimSound";
-	WNDCLASS wndclass = { 0, sound_wndproc, 0,    0, g_hinst, NULL, 0,
-			      0, NULL,          clazz };
-	RegisterClass(&wndclass);
-	g_hWndSound = CreateWindow(clazz, NULL, 0, 0, 0, 0, 0, HWND_MESSAGE,
-				   NULL, g_hinst, NULL);
+        LPCSTR clazz = "VimSound";
+        WNDCLASS wndclass = { 0, sound_wndproc, 0,    0, g_hinst, NULL, 0,
+                              0, NULL,          clazz };
+        RegisterClass(&wndclass);
+        g_hWndSound = CreateWindow(clazz, NULL, 0, 0, 0, 0, 0, HWND_MESSAGE,
+                                   NULL, g_hinst, NULL);
     }
 
     return g_hWndSound;
@@ -362,14 +362,14 @@
     WCHAR *wp;
 
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     wp = enc_to_utf16(tv_get_string(&argvars[0]), NULL);
     if (wp == NULL)
-	return;
+        return;
 
     if (PlaySoundW(wp, NULL, SND_ASYNC | SND_ALIAS))
-	rettv->vval.v_number = ++sound_id;
+        rettv->vval.v_number = ++sound_id;
     free(wp);
 }
 
@@ -385,7 +385,7 @@
     MCIERROR err;
 
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     filename = tv_get_string(&argvars[0]);
 
@@ -393,25 +393,25 @@
     p = alloc(len);
     if (p == NULL)
     {
-	return;
+        return;
     }
     vim_snprintf((char *)p, len, "open \"%s\" alias sound%06ld", filename,
-		 newid);
+                 newid);
 
     wp = enc_to_utf16((char_u *)p, NULL);
     free(p);
     if (wp == NULL)
-	return;
+        return;
 
     err = mciSendStringW(wp, NULL, 0, sound_window());
     free(wp);
     if (err != 0)
-	return;
+        return;
 
     vim_snprintf(buf, sizeof(buf), "play sound%06ld notify", newid);
     err = mciSendStringA(buf, NULL, 0, sound_window());
     if (err != 0)
-	goto failure;
+        goto failure;
 
     sound_id = newid;
     rettv->vval.v_number = sound_id;
@@ -419,9 +419,9 @@
     soundcb = get_sound_callback(&argvars[1]);
     if (soundcb != NULL)
     {
-	vim_snprintf(buf, sizeof(buf), "sound%06ld", newid);
-	soundcb->snd_id = newid;
-	soundcb->snd_device_id = mciGetDeviceID(buf);
+        vim_snprintf(buf, sizeof(buf), "sound%06ld", newid);
+        soundcb->snd_id = newid;
+        soundcb->snd_device_id = mciGetDeviceID(buf);
     }
     return;
 
@@ -437,7 +437,7 @@
     char buf[32];
 
     if (in_vim9script() && check_for_number_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     id = tv_get_number(&argvars[0]);
     vim_snprintf(buf, sizeof(buf), "stop sound%06ld", id);
@@ -458,7 +458,7 @@
     CloseWindow(g_hWndSound);
 
     while (first_callback != NULL)
-	delete_sound_callback(first_callback);
+        delete_sound_callback(first_callback);
 }
 #  endif
 
@@ -469,7 +469,7 @@
 sound_play_common(typval_T *argvars, typval_T *rettv, bool playfile)
 {
     if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
-	return;
+        return;
 
     char_u *sound_name = tv_get_string(&argvars[0]);
     soundcb_T *soundcb = get_sound_callback(&argvars[1]);
@@ -479,7 +479,7 @@
     bool play_success = sound_mch_play(sound_name, sound_id, soundcb, playfile);
     if (!play_success && soundcb)
     {
-	delete_sound_callback(soundcb);
+        delete_sound_callback(soundcb);
     }
     rettv->vval.v_number = play_success ? sound_id : 0;
 }
@@ -500,7 +500,7 @@
 f_sound_stop(typval_T *argvars, typval_T *rettv UNUSED)
 {
     if (in_vim9script() && check_for_number_arg(argvars, 0) == FAIL)
-	return;
+        return;
     sound_mch_stop(tv_get_number(&argvars[0]));
 }
 
@@ -516,7 +516,7 @@
 {
     sound_mch_free();
     while (first_callback != NULL)
-	delete_sound_callback(first_callback);
+        delete_sound_callback(first_callback);
 }
 #  endif