Index: Plug.tmpasm
===================================================================
--- Plug.tmpasm	(revision 38350)
+++ Plug.tmpasm	(revision 38351)
@@ -1,5 +1,8 @@
 put /local/rnd/mod {fontmode}
-put /local/rnd/mod/OBJS [@ $(PLUGDIR)/fontmode/fontmode.o @]
+put /local/rnd/mod/OBJS [@
+	$(PLUGDIR)/fontmode/fontmode.o
+	$(PLUGDIR)/fontmode/preview.o
+@]
 
 switch /local/module/fontmode/controls
 	case {buildin}   include /local/pcb/tmpasm/buildin; end;
Index: fontmode.c
===================================================================
--- fontmode.c	(revision 38350)
+++ fontmode.c	(revision 38351)
@@ -58,6 +58,7 @@
 #include "event.h"
 #include "polygon.h"
 #include "obj_poly_draw.h"
+#include "preview.h"
 
 /* FIXME - we currently hardcode the grid and PCB size.  What we
    should do in the future is scan the font for its extents, and size
@@ -715,7 +716,8 @@
 	{"FontXform", pcb_act_FontXform, pcb_acth_FontXform, pcb_acts_FontXform},
 	{"FontSetXdelta", pcb_act_FontSetXdelta, pcb_acth_FontSetXdelta, pcb_acts_FontSetXdelta},
 	{"FontNormalize", pcb_act_FontNormalize, pcb_acth_FontNormalize, pcb_acts_FontNormalize},
-	{"FontBaseline", pcb_act_FontBaseline, pcb_acth_FontBaseline, pcb_acts_FontBaseline}
+	{"FontBaseline", pcb_act_FontBaseline, pcb_acth_FontBaseline, pcb_acts_FontBaseline},
+	{"FontModePreview", pcb_act_FontModePreview, pcb_acth_FontModePreview, pcb_acts_FontModePreview}
 };
 
 static const char *fontmode_cookie = "fontmode plugin";
Index: preview.c
===================================================================
--- preview.c	(nonexistent)
+++ preview.c	(revision 38351)
@@ -0,0 +1,69 @@
+/*
+ *                            COPYRIGHT
+ *
+ *  pcb-rnd, interactive printed circuit board design - font editor preview dlg
+ *  Copyright (C) 2023 Tibor 'Igor2' Palinkas
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Contact:
+ *    Project page: http://repo.hu/projects/pcb-rnd
+ *    lead developer: http://repo.hu/projects/pcb-rnd/contact.html
+ *    mailing list: pcb-rnd (at) list.repo.hu (send "subscribe")
+ */
+
+#include <librnd/core/config.h>
+#include <librnd/hid/hid_dad.h>
+
+typedef struct{
+	RND_DAD_DECL_NOINIT(dlg)
+	int active; /* already open - allow only one instance */
+} fmprv_ctx_t;
+
+fmprv_ctx_t fmprv_ctx;
+
+static void fmprv_close_cb(void *caller_data, rnd_hid_attr_ev_t ev)
+{
+	fmprv_ctx_t *ctx = caller_data;
+	RND_DAD_FREE(ctx->dlg);
+	memset(ctx, 0, sizeof(fmprv_ctx_t)); /* reset all states to the initial - includes ctx->active = 0; */
+}
+
+static void pcb_dlg_fontmode_preview(void)
+{
+	rnd_hid_dad_buttons_t clbtn[] = {{"Close", 0}, {NULL, 0}};
+
+	if (fmprv_ctx.active)
+		return; /* do not open another */
+
+	RND_DAD_BEGIN_VBOX(fmprv_ctx.dlg);
+		RND_DAD_COMPFLAG(fmprv_ctx.dlg, RND_HATF_EXPFILL);
+		RND_DAD_LABEL(fmprv_ctx.dlg, "fmprv");
+		RND_DAD_BUTTON_CLOSES(fmprv_ctx.dlg, clbtn);
+	RND_DAD_END(fmprv_ctx.dlg);
+
+	/* set up the context */
+	fmprv_ctx.active = 1;
+
+	RND_DAD_NEW("font_mode_preview", fmprv_ctx.dlg, "Font editor: preview", &fmprv_ctx, rnd_false, fmprv_close_cb);
+}
+
+const char pcb_acts_FontModePreview[] = "FontModePreview()\n";
+const char pcb_acth_FontModePreview[] = "Open the font mode preview dialog that also helps editing font tables";
+fgw_error_t pcb_act_FontModePreview(fgw_arg_t *res, int argc, fgw_arg_t *argv)
+{
+	pcb_dlg_fontmode_preview();
+	return 0;
+}
Index: preview.h
===================================================================
--- preview.h	(nonexistent)
+++ preview.h	(revision 38351)
@@ -0,0 +1,3 @@
+extern const char pcb_acts_FontModePreview[];
+extern const char pcb_acth_FontModePreview[];
+fgw_error_t pcb_act_FontModePreview(fgw_arg_t *res, int argc, fgw_arg_t *argv);