The ornamental design for a door of a toolcart, as shown and described.
FIG. 1 is a perspective view of a door of a tool cart showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left elevation view thereof;
FIG. 5 is a right elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof, in condition of use.
The broken lines showing portions of a door are for the purpose of illustrating portions of a door of a tool cart and form no part of the claimed design. The broken lines showing a cart are for the purpose of illustrating environment and form no part of the claimed design.