Problem Interaction Between Fldigi and Xfce4

Robert G Snyder bob at
Mon Mar 6 06:18:43 CET 2023

Recently, a change to the code in fldigi, a popular, cross platform, 
amateur radio digital mode application caused xfwm4 and xfce4-panel 
running on Arm (RPi 4B) under debian bullseye 64-bit to crash.No 
problems on Intel systems. The initial reaction was that something got 
broken in fldigi.

However, when testing with LXDE desktop manager and LXPanel 0.10.1 and 
also MATE desktop manager, no problems were encountered. So our best 
conclusion for now is that the problem is in Xfce4.

Note that fldigi uses fltk for GUI functionality. Dave Freese, the 
primary developer of fldigi, has isolated the code in fldigi that 
triggers the problem:

        // See
        // read in the current window hints, then modify them to allow 
icon transparency
        Pixmap mask = -1;
        XWMHints* hints = XGetWMHints(fl_display, fl_xid(arqwin));
        hints->flags |= IconMaskHint; // ensure transparency mask is 
enabled for the XPM icon
        hints->icon_mask = mask; // set the transparency mask
        XSetWMHints(fl_display, fl_xid(arqwin), hints);

Although Dave has a workaround, we are hoping that the problem can be 
found or at least we can work together to fix this. fldigi is under GPL 
Ver 3. Versions with and without the problem are available.


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