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From: richard@unipalm.co.uk
Newsgroups: comp.windows.x.motif
Subject: Bug in Sash with multiple displays
Message-ID: <9102121454.AA17703@ariel.unipalm.co.uk>
Date: 12 Feb 91 14:54:39 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 99




                          OSF Problem Report
                  =================================

Submitter Name:         Richard Nuttall
Organization:           Unipalm Limited
Email Address:          richard@unipalm.co.uk
Phone:                  +44 954 211797
OSF License Number:     845-F-S-90

Hardware/Software Configuration
- -------------------------------

Offering and Version:   Motif 1.1.0.2
Component (Module):     Xm Sash.c
Client Hardware:        SPARCstation 1+
Client Software:        SunOS 4.1
Server Hardware:        SPARCstation 1/GX, Sun3/60
Server Software:        Unipalm XTech X11R4 + 1-18.
Compiler:               SunOS 4.1 cc

Problem Description
- -------------------

Severity Level: 		Fatal

Date of First Occurrence: 12-Feb-91

One Line Description:

        Sash caches the crosshair cursor, which doesn't work for multiple displays.

Full Description:

        The crosshair cursor used by the Sash is created only once
        and then the same cursor is returned for future Sashes.
        Since the cursor created is display specific, A protocol
        error results when trying to realise a Sash on more than
        one display from the same application.

Repeat By:
(edited fragments from large program)
        [...]
        dpy1 = XtOpenDisplay(...,"machine1:0",....);
        dpy2 = XtOpenDisplay(...,"machine2:0",....);
        top1 = XtAppCreateShell("Shell1", "Xapp",
                   applicationShellWidgetClass, dpy1, NULL, 0);
        top2 = XtAppCreateShell("Shell2", "Xapp",
                   applicationShellWidgetClass, dpy2, NULL, 0);
        [...]
        PW1 = XmCreatePanedWindow(top1, "PW1", NULL, 0);
        PW2 = XmCreatePanedWindow(top2, "PW2", NULL, 0);
        [...]
        XtRealizeWidget(top1);
        XtRealizeWidget(top2); /* error occurs here */

Proposed Solution:
(Quick hack)

*** /bold/files/motif/sun4/lib/Xm/Sash.c        Mon Oct  9 10:50:01 1989
--- Sash.c      Tue Feb 12 14:08:32 1991
***************
*** 254,261 ****
  }


- static Cursor SashCursor=NULL;
-
  static void Realize(w, p_valueMask, attributes)
      register Widget w;
      Mask *p_valueMask;
--- 254,259 ----
***************
*** 262,270 ****
      XSetWindowAttributes *attributes;
  {
     Mask valueMask = *p_valueMask;

-    if (SashCursor==NULL)
-          SashCursor=XCreateFontCursor(XtDisplay(w), XC_crosshair);
      attributes->cursor = SashCursor;
      valueMask |= CWCursor;

--- 260,267 ----
      XSetWindowAttributes *attributes;
  {
     Mask valueMask = *p_valueMask;
+    Cursor SashCursor = XCreateFontCursor(XtDisplay(w), XC_crosshair);

      attributes->cursor = SashCursor;
      valueMask |= CWCursor;


A better solution would be to check the display and cache one cursor
per display.
I have not considered any memory leaks that might be caused by creating
lots of cursors but not destroying them.