[news.eclipse.platform.rcp] Action set, Editor input

[Geri Broser <gerold.broser@xxxxxxxxxxxxx>]

I have to create an app to open a (text, html, xml) file and to process 
its contents. So far, i managed to open such files in an editor (with 
syntax coloring; code folding and line numberung would be nice, but it's 
not essential).

This was very helpful to achieve this: 
http://www.eclipse.org/eclipse/platform-text/development/rcp/examples/index.html

However, now I'm stuck at the following issues:

1) I defined three action in an action set in plugin.xml: OpenFile, 
Sign, Verify.

1.1) OpenFile, which I took from the example mentioned above, works as 
intended: Selecting File --> Menu or the appropriate toolbar button 
accesses the proper class OpenFileAction which loads a file into an 
appropriate editor.

1.2) Sign and Verify are displayed in the appropriate menu and in the 
main tool bar. But, when I select either of them an Information msgbox 
appears with the following text: "This operation is not available at the 
moment."

Q1: Where am I wrong?

Q2: Would it be better to add the actions via an editorContribution 
(like in 
http://www.eclipse.org/articles/Article-action-contribution/index.html)? 
With the advantage of disabled menu items, unless an editor window is 
opened? But, as extension to WHICH editor? There are three used in the 
text editor example above: AbstractTextEditor, SimpleEditor, XMLEditor.

2) When I add Sign and Verify via ApplicationActionBarAdvisor, the 
proper classes are accessed, of course. The disadvantage is that this 
seems only to be useful for menu items. When I add actions to the 
toolbar there, labels are displayed, not icons. And the items are active 
even if there's nothing to do (no editor has been opened).

Q3: How do I get the contents of the currently active editor?

Q4: How do I open an empty editor and fill it with contents (to display, 
and optionally save, changed data without harming the original file)?

Geri