I'm currently working on an application using the 0.86 version of the
forms library. The main application uses a number of transient forms
containing canvas (or is is canvai?). If a form holding a canvas is
hidden `fl_hide_form' the canvas window seems to be deleted, and the
new window needs to be initialised again after `fl_show_form'.
This behaviour also causes `BadDrawable' in the following scenario:
An application handles a main form and a transient form.
The trancient form is composed of a canvas and a menu button.
The canvas has registered to receive `Expose' events.
One of the menu call backs causes a `fl_hide_form' on the trancient
form when the `Hide' item is selected. However, when the `Hide' item
is selected an `Expose' event is generated, but `fl_hide_form' is
executed before the event is received. The `Expose' handler then
receives the event, draws in the killed canvas window and causes a
`BadDrawable' error event.
I am not totally certain wether this is the actual way thing go wrong,
but testing the window tree repeatedly using `xwininfo' on the
transient window tells me that the XID of the canvas window changes
after a `fl_hide_form' `fl_show_form'.
A few other error events has also occured, all of which can be
explained with trying to handle events for the killed canvas window.
Has anyone else had problems like this, maybe even worked out a usable
work-around? I'm extremely reluctent to move my application into
Motif as I am very happy with the forms library.
/Mats
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