Powerbi/Power Query Editor dropdown/filter not showing

[billlyh96]

I am currently using power bi and am transforming the data using power query editor. As shown in the image below, why does alot of my column not show any filter data under the drop down ? 
I do have a big data load but is that the only reason why it is unable to show due to the large set of data in it ? It has only about 7 different type of values under sales channel.
With this issue , i'm unable to filter the sales channel accordingly. And if so, is there any other way i am able to filter the data to show specifically a few of the selected sales channel everytime I power query it ?
Please do help me with this issue. Thank you ! 

[christinepayton]

If you want to filter on things that are not present in the dropdown, just select the "text filters" option in your screenshot and type in the values there. There's also the option to not use the 1000 row preview in the bottom corner of the PQ window if you want to try toggling that to see all values.