By using the documents of the Styrian Landesarchiv in Graz we continued the research of Gruber, Kunsti, Vega, and other engineers working on the Mura River, which we previously began in an older publication using the documents of the Archive of Slovenia. While we formerly published documents about Vega's work in 1779/80 we now claimed that he had also regulated the river Mura during three previous years. We examined Gruber's engineers drawings of the navigational plans and compared their style with the works of their contemporaries. For the first time we discussed the documents about Gruber's engineer Vega's resignation and the very first Kunsti's use of name "Vega" instead of the older original form "Veha". Vega became the artillerist at Vienna and famous mathematician soon afterwards. We made some rough guesses about the reasons, why Josef II did not support Gruber's navigation work after 1780. The change of Vienna court politics was one of the reasons for Vega's move to Vienna as well as for later Gruber'sfare well of the Habsburg monarchy.