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[STR Pending]

Link: https://www.fltk.org/str.php?L3521
Version: 1.4-feature


I tried to process wheel+shift events as equivalent
to horizontal movements by doing this starting at
line #1973 of file src/Fl_x.cxx :

  case ButtonPress:
    Fl::e_keysym = FL_Button + xevent.xbutton.button;
    set_event_xy(window);
    Fl::e_dx = Fl::e_dy = 0;
    if (xevent.xbutton.button == Button4) {
      Fl::e_dy = -1; // Up
      event = FL_MOUSEWHEEL;
    } else if (xevent.xbutton.button == Button5) {
      Fl::e_dy = +1; // Down
      event = FL_MOUSEWHEEL;
    } else if (xevent.xbutton.button == 6 || (xevent.xbutton.button ==
Button4 && xevent.xbutton.state & ShiftMask)) {
	Fl::e_dx = -1; // Left
	event = FL_MOUSEWHEEL;
    } else if (xevent.xbutton.button == 7 || (xevent.xbutton.button ==
Button5 && xevent.xbutton.state & ShiftMask)) {
	Fl::e_dx = +1; // Right
	event = FL_MOUSEWHEEL;
    } else {
      Fl::e_state |= (FL_BUTTON1 << (xevent.xbutton.button-1));
      event = FL_PUSH;
      checkdouble();
    }

But, on my setup which is Ubuntu within Virtualbox on macOS,
something swallows altogether events when the mouse wheel
is moved AND shift is pressed: function fl_handle(const XEvent& )
doesn't even run. That is possibly caused by VirtualBox on macOS
since you report that shift+wheel with the patched Fl_Scrollbar.cxx
does activate the horizontal scroll with VirtualBox on windows.


Link: https://www.fltk.org/str.php?L3521
Version: 1.4-feature