Volume 6A: Motif Programming Manual

Widget text_w;

Arg args[5];

int n = 0;

...

XtSetArg (args[n], XmNdropSiteActivity, XmDROP_SITE_INACTIVE); n++;

XmDropSiteUpdate (text_w, args, n);

...

Even though drop sites are associated with widgets, you have to set DropSite resources using

XmDropSiteUpdate(), not XtVaSetValues().

One situation in which you would probably want to disable a built−in drop site is when the widget is designed to be

output−only. If you set the XmN-editable resource of a Text or TextField widget to False, the user cannot drop

data in the widget because it is uneditable. However, the toolkit still displays the default drag−under visual effects in

this case, so the widget appears as though it functions as a drop site. To make it clear that the widget is not a drop site,

you can disable the drop site using one of the techniques we just described. If the widget is always uneditable, it is

fine to use XmDropSiteUnregister(), but if the widget changes state, you are better off setting

XmN-dropSiteActivity.

When you set a Text or TextField widget insensitive, the user cannot interact with the widget, so it doesn't make sense

for the widget to function as a drop site. However, there is currently a bug in the implementation of drag and drop

such that the user can drop text in an insensitive widget. To prevent this problem, whenever you change the sensitivity

of a Text widget, you should set the XmN-dropSiteActivity resource to match the sensitivity.

19.3.3 Modifying the Visual Effects

Motif provides resources that both ...