Shading/Hatching is currently a bit complex. The bad news is that it will become worse.
As an option (look at File/Document properties), shading can be either the classical “cross-line shading” you can see in old publications, or a light gray background. Although many users prefer the first one out of tradition, the second is indeed typographically superior. Cross-line shading makes signs difficult to read, which is not the case of the light gray background.
Shading comes in a number of flavors. This is due to the Manuel de Codage's history.
A good summary is available in the JSesh sample document (the one which used to appear when you started JSesh, and which is now included in the JSesh text library (in the next version, that is)).
But, to tell the whole story:
The menu entry in Text Manipulation/Shading can apply to a selection. That is, you can shade the top part of all groups in a selection in one operation (previously, you had to shade each group individually).
More, for people who type texts with lots of lacunas, I have added a popup menu. If you press the “#” key on your keyboard, this menu will appear. You can navigate in it with the keyboard or select entries by a specific letter.
Now I can select the shading I need by various means (it depends on your computer system). For instance, I can type “3”, move in the menu with the keyboard arrows or select the menu item with the mouse. Then, the whole selected text is shaded:
If you want, for instance, to add a shaded zone over the middle of a sign, you can now do it. In fact, it's the reason why I added a menu to retrieve the “old” shading symbols. Let's say you want to create . You first need to enter both signs. The shading is added through the menus :
Then, you simply need to use the group editor:
You should probably enter the shading symbol first, and then the glyph. This way, if your final output format doesn't understand transparency, you will still have a correct rendering.
(By the way, ecdotic marks like [ … ] are also glyphs. As such, they can be moved in the group editor).