In an action by a broker for compensation on the issue as to whether the contract with the principal called for a commission of a certain percentage of the proceeds of the sale, or of the proceeds over a specified price, evidence as to defendant's dealings with other real estate agents, and the terms under which he had listed the land with them, was inadmissible. Lloyd v. Kerley (Tex. Civ. App. '07), 106 S. W. 696; Boss v. Carr (N. M. Sup. '09), 103 P. 307; Leander v. Graves (Colo. Sup. '09), 100 P. 403; Steinman v. Henry Morganthau Co., 154 N. Y. Sup. 216; Engles v. Blocker, 192 S. W. 193, 127 Ark. 385.