Furniture Parameter

[LanggamanXavierMassed]

Can you not edit table length parameter if it is set on instance parameter? I put it at instance and the measurement is greyed out but I did another Length set to be Type and it can.. I would appreciate an explanation, thank you so much!

[L.Maas]

Depends how the family is created. Consider uploading it so we can have a look

If in the family the instance parameter has a formula then it can not be changed because it is controlled by that formula

[barthbradley]

By the sound of it, you are looking at an in-built template parameter. In-built parameters cannot be modified or removed.  The solution would be to use another Template, or simply not use the in-built to drive any dimensions. Instead, create your own length parameter (w/ different name), and label your dimension with that new parameter.  

Example of Built-In Parameter "Height" in Window Template: