Just call DockableForm.Activate() to activate/select a DockableForm.

Where do you want to set a maximum number of characters? Are you referring to the title of a DockableWindow?

The Text Editor Control does not directly support that. There is no property to set the max number of characters. 

What kind of errors? Can you be more precise?

The control has troubles rendering long lines (lots of characters in a single line). This is a known problem.

No, this is not possible. The reason is that in some situations it is impossible to enforce such size constraints.

Just imagine two DockableForms: The first requires a minimum size of 200 x 200. The second has a maximum size of 100 x 100. It would not be possible to dock these forms in the same DockPane or next to each other. It is also no longer possible to dock one of the forms in the document area (center) because forms in the center are always stretched to fill the document area.

That is the reason why DockableForms should be resizable.