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Bug 328287

Summary:	Eclipse e4 RCP apps should support for D&D of workbench parts
Product:	[Eclipse Project] e4	Reporter:	Lars Vogel <Lars.Vogel>
Component:	UI	Assignee:	Project Inbox <e4.ui-inbox>
Status:	RESOLVED WORKSFORME	QA Contact:
Severity:	normal
Priority:	P3	CC:	Lars.Vogel, remy.suen, tom.schindl
Version:	unspecified
Target Milestone:	---
Hardware:	PC
OS:	Windows 7
Whiteboard:

Description Lars Vogel

2010-10-20 15:46:01 EDT

Eclipse 3.x does support D&D for parts out of the box if you create a new app. For Eclipse e4 application you need to add a dependency to the plugin “org.eclipse.e4.ui.workbench.addons.swt” and add the Add-On “org.eclipse.e4.ui.workbench.addons.dndaddon.DnDAddon” to your “Application.e4xmi”. 

I think we second part should be automatic, if the plugin is included then D&D should be enabled in the RCP app.

Comment 1 Eric Moffatt

2010-10-20 16:06:57 EDT

This is a really nice pattern...a plug-in with a snippet extension that adds the addon to the model seems like nice packaging to me...

Note that there are some subtle inter-dependencies here. For example if you take the standard DnD addon then you will likely need some form of the Cleanup addon as well. 

This is because when you drag a part out to create a new stack it implicitly generates a new PartSashContainer to contain then new stack and the one it was 'splitting'. But...when you drag the part back to its original stack you probably want the (now empty) stack to be removed from the model and since the PartSashContainer now only contains one child you likely want to get rid of it as well (otherwise repeating these actions will build up many (unnecessary) instances of sash containers (we refer to this as the 'hall of mirrors...;-).

As a side note...we're trying to keep the amount of code in the various addons small enough that they are as easy as possible for someone to copy it and make domain specific modifications (i.e. our cleanup addon specifically will *not* un-render the last EditorStack, even if it's empty).

I hope that this pattern leads to less API...we could have a full-fledged DnD api (registerDragAgent...) that would allow clients to customize the behavior or we can say 'take a copy of the addon and modify it to suit your particular needs'. This will work only if a particular addon is small enough to get your head around in a few *hours* max.

Comment 2 Thomas Schindl

2010-10-20 16:07:08 EDT

-1 for many RCP applications this is causes more confusion and there are multiple request from people to turn this feature of in 3.x

Comment 3 Lars Vogel

2010-10-20 16:12:39 EDT

Actually Tom is correct. Most users hate this feature and request to turn it off.

-1 from me too. 

Feel free to close this bug.

Comment 4 Remy Suen

2010-10-20 16:38:52 EDT

Not exactly difficult for someone to opt-in. It's "only" difficult right now because we have no documentation.

Comment 5 Eric Moffatt

2010-10-26 14:38:55 EDT

+1 for the idea that most folks don't want this in simpler (non-ide) apps. This is in line with the story that in e4 you *include* what you want rather than wiring off everything you don't need.

The pattern still works though (i.e. you get the addon installed through a model snippet if you have a dependency on the bundle. I'll see if I can factor up the DnD this way.