In the 7zip GUI, it's hard to start with a blank compressed file. I suggest adding something under File/New for each type of supported compressed file.
I see #7zip:matrix.org but I don't think its official. Only 6 people in there. If it is official, add a link to the support page.
It'd help if it were possible to create blank 7z files. I see two methods as outlined below. It'd help if 7-Zip offered both. In Explorer, if you look at the context menu for a folder, it lists a submenu called "New". Under there, you see new text files, folders, and zip files--but no 7z file. In 7-Zip File Manager, add a New submenu to the File menu listing 7z followed by a separator and then all other supported formats.
Rotatable shapes now need to point up when the course is 0. Also, shapes must have no stroke on the first element.
The class Tab is now longer part of the project
Application now can display tabs
Replaced SVG packages that weren't working with SharpVectors and changed how the default directory during debug runs to be relative. Also deleted the Tab Bkg.svg file as that isn't used anymore.
Reorganized layout