The SH3MissionEditor likes one screen resolution, and one only. It also does not like if you have a widescreen mod enabled. You must also start the MissionEditor in the game folder that you are attempting edits in. You can somewhat alleviate the 1024x768 resolution issue by changing the SH3MissionEditor.exe "Properties" page for the "Compatibility" settings. On one of my computers, I have nothing clicked. On another computer, I have "Disable fullscreen optimizations" ticked. It takes experimentation with those settings, since no two computers are alike. If you do not disable any widescreen mod you have running though, you will have issues with the screen drawing properly, AND with the editor actually saving edits properly, destroying your hard work behind your back... If you have a widescreen utility running, create a mod folder (such as "D3Dfiles") in the MODS folder. Select the widescreen D3D.dll and D3D.ini files and "Cut" them. "Paste" them into the "D3Dfiles" folder in the MODS folder. You can then re-activate them after you complete your ME edits. If you have to do further edits, de-activate the "D3Dfiles" mod, and run SH3ME again. As a side note, the D3D.dll file will not remove itself from the game if you have Discord and some other graphics apps open...
