Editorize summons up your favorite text editor with a global shortcut so that you can edit your text the way you want it. Close the file and the text automagically gets pasted in to the text field you were editing.
Editorize is in beta and needs some bugfixes/cleanup before it can be considered stable.
The easiest way to install editorize is by using the ppa:
sudo apt-add-repository ppa:tuxcanfly/editorize
After that, updated and install the editorize package:
sudo apt-get update
sudo apt-get install editorize
Source packages are available from the launchpad project page.
Now you should be able to launch the app from the start menu / dash or using the command editorize
The default global keyboard shortcut for launching your default text editor is:
<Ctrl><Alt>i
Both the shortcut and text editor can be customized from the Preferences menu of the App Indicator.
Just go to a text input field on any app and use the above keyboard shortcut and your text editor should pop open. Now enter your text, save and close the editor. The input text should get copied to the app.
Please report bugs on launchpad