.Net - ToolControl closing form

edited February 2023 in GeoStudio
I'm developping some custom tools in Montaj .Net and I'm using ToolControl form for my user interaction. When I'm opening my Montaj project, I see multiple ToolControl window flashing like the software open each form I opened in my previous session and it's making the loading longer by each opening of the same project. When I'm opening a newly created project, I don't have these flashing windows. I think it's because I'm not closing my forms when I'm done with them but I didn't found any control to close the form. Does somebody encountered this problem and found a solution?