[Mechjeb tab not showing at all]

 

[Mechjeb 2 menus not showing up]

Hi i too had the same problem. After a whole day of trying to fix it,  i removed the whole mod and then reinstalled the mechjeb mod according to the version of ksp i have (1.3.1). And to my surprise it worked really well. Here is the link try to find your version of the game and install it :https://www.curseforge.com/kerbal/ksp-mods/mechjeb/files