Access not allowing users to delete rows -

I have a problem being able to delete the lines of data in the form (for example, if I need to delete one Line which I just repeated, I can not do this) Here's a little bit about my database. I have three different residences (forest, wetland, grassland) and each place has its own data entry form to enter the list of species coming to each site. The only difference in the form is the name, all the codes are the same, as are the settings of the forms and controls. Forms include a main form (forest suspension) and a subform (vegetasbusform).

My problem is that I can not remove rows of data in wild form. I click on the box at the far left of the line to select it, and then right click to delete it, and the selection of "deleted records" is grayed out. I can not just remove it from being removed, either .

I have run "documentary" to check the settings of the main form and sub form twice and both allow "allow allow" is correct, so technically I can delete the record, but I can not Does anyone have any ideas to cause this problem?