opening modal windows from the "button-press-event" handler forclist

[Vlad Harchev <hvv hippo ru>]

 Hello, list!

 Here is problem I have. I need to handle right clicks in clist (right
click is used as "marking" in my app - "marked" items change color). It's
disallowed to mark some items in the clist in my app so I want to pop up a 
modal error window when user tries to mark such items. But with 
straightforward implementation, just creating modal window freezes X server
(if this code is executed from console, it's possible to kill this app - 
beware!). A stripped down code I use is at the end of the message.

 How this problem could be avoided?

 I use stock RH6.0's gtk+1.2.1-10 on x86 box. I use XF86_S3 from RH6.0.

 Thanks in advance.

 Best regards,
  -Vlad
---------------------------
#include <string.h>
#include <stdio.h>
#include <gtk/gtk.h>

/*this function works fine when not called from handler 'button-press-even' of
clist, and freezes X server otherwise. */
void error_message(const char* title,const char* text)
{
    GtkWidget *dialog;
    GtkWidget *button,*hb,*l;
    char* str;

    dialog = gtk_dialog_new();
    gtk_window_set_title (GTK_WINDOW (dialog), title);    

    l = gtk_label_new(text);

    hb = gtk_hbox_new(1,0);
    gtk_box_pack_start (GTK_BOX (hb), l, TRUE, TRUE, 43);    
    gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog)->vbox),
		hb, TRUE, TRUE, 0);			    
    button = gtk_button_new_with_label("OK");
    gtk_signal_connect_object(GTK_OBJECT(button),"clicked",
	GTK_SIGNAL_FUNC(gtk_main_quit),GTK_OBJECT(dialog));
    gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog)->action_area),
                            button, TRUE, TRUE, 0);
    gtk_window_set_modal (GTK_WINDOW(dialog),TRUE);
    GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
    gtk_widget_grab_default (button);
	        
    gtk_widget_show_all(dialog);
    gtk_main();    
    gtk_window_set_modal (GTK_WINDOW(dialog),0);
    gtk_widget_destroy(dialog);    
};


void sig_select_row(GtkWidget *w,GdkEventButton *e)
{
    gdk_event_free(e);/*removing this call won't help*/
    error_message("Hello","Hello, world");
};

int main(int argc,char** argv)
{
    GtkWidget *window,*l;
    char* str = "FOO";
    int i;
    
    gtk_init (&argc, &argv);
    
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    l = gtk_clist_new(1);
    for(i=0;i<10;++i)
	gtk_clist_append(GTK_CLIST(l),&str);

    gtk_signal_connect_after(GTK_OBJECT(l),"button-press-event",
	GTK_SIGNAL_FUNC(sig_select_row),NULL);	
    gtk_container_add(GTK_CONTAINER(window),l);
    gtk_widget_show_all(window);
    gtk_main ();    
};