See fltk.general, thread "Is handling simultaneous Left-click and
Right-click drags supported?" from Jul 12, 2023
Status: FL_DRAG operation is terminated when one mouse button is
released, even if more than one button is actually down. Subsequent
mouse movement is reported as FL_MOVE rather than FL_DRAG, this is
under investigation.
FL_OVERRIDE is defined as `override` for C++11 and higher
FL_OVERRIDE is defined as `override` for VisualC 2015 and newer
Don't interfere with Fl_Widget::override()
Output was incorrect, partly to stdout and stderr, resp.
As Manolo noted in fltk.general, Fl_Window::screen_num() is the
correct API to retrieve the screen number of a window rather than
Fl::screen_num(...).
This is intended to be used as
(a) an example of event handling and
(b) a test program to visualize many event related variables
This first version is compatible with FLTK 1.3.x but lacks the screen
scaling factor under 1.3.x (which is always assumed to be 100%).
Note: this does not reflect any system or monitor related settings.
