More Morphic snags

I have been trying to replicate the behaviour of an existing (non-Pharo,
non-Smalltalk) application with Morphic. This provides grouping images
in a workspace, and then switching between laying them out separately or
"stacked" by double clicking on the group (or an image in it). When the
group is stacked, it can be moved around as a single drag and drop
operation. When the group is separated, dragging an image out of it
removes it from the group.

On the surface this looked like a perfect fit to the submorph tree. 
Unfortunately, as both the Morphic chapter in Pharo by Example and the
intro document by Maloney make clear, if you enable double clicking (by
answering true to #handlesMouseDown:), you are interfering with what
Maloney calls the "default behaviour" of being able to drag a Morph around.

How do I reinstate that behaviour if a group is clicked on and the
double click does not happen? Neither document helps in explaining where
that "default" can be found in the code.

Thanks
Markus

Markus Stumptner <[hidden email]> wrote:
> How do I reinstate that behaviour if a group is clicked on and the
> double click does not happen? Neither document helps in explaining where
> that "default" can be found in the code.

Take a look at the code for the drag panels. I have some videos starting at
https://vimeo.com/130781061
I’m not sure the configurations are up to date for Pharo 7

Stephan

On Sun, 2 Jun 2019 at 00:18, Markus Stumptner <[hidden email]> wrote:
Have you put a `self haltOnce` in #handlesMouseDown: ?

I am far from an expert here, but the following may help:

Three alternate ways of handling mouse events
https://wiki.squeak.org/squeak/2477
http://squeak.preeminent.org/tut2007/html/078.html

Check the Dragging section here...
https://wiki.squeak.org/squeak/6194

Search for doubleclick here...
https://course.ccs.neu.edu/com3230/squeak/SqueakMorphClassGuide.pdf

a few more #handlesXXX methods...
https://course.ccs.neu.edu/com3230/squeak/SqueakMouseControls.html

cheers -ben