AvalonDock : DockableContent Context Menu Shows wrong list of menus

Question

i am using AvalonDock : DockableContent. when i right click, i am getting

1. Float
2. Show[disabled]
3. Dock as Tabbed Document
4. Auto Hide

when i click float and right click, the context menu changes as like this

1. Show
2. Hide
3. Dock as Tabbed Document
4. Float [Enabled]
5. Float [Disabled]

there are two floats instead of dock and float and clicking on one float enables the other and disables it. so no docking happens. it is not even spelling mistake. how to correct this mistake and bring dock instead of one enabled float.

Due to this reputation issue, i am not able to post the exact picture of context menu.

Please give some tips to resolve this issue.

Thank you,