The canvas is still redrawing even with a locked solver, and this error is because of canvas painting.
Wires are drawn one after the other, so even though it will take a longer time to draw lots of wires, it shouldn’t take more memory. Unless of course there’s a bug in that code.
Unfortunately the ‘Out of memory’ error is what GDI+ almost always says when something goes wrong, it doesn’t necessarily mean that you are out of memory, although it may be true as well. The problem is that GDI allocates a fixed amount of memory for certain operations and if something weird happens that small amount may run out. You cannot change this amount, it is hard-coded by the operating system.
Most often when GDI starts to fail it is because things are drawn too far away from the origin. You can try and move all your objects to be centred on (0,0), or in general reduce the size/extent of the file.
I would like to have the file as well so I can do some testing here. Either find a bug, or maybe come up with some ways to try and solve these problems.
ps. you can exit the ‘red-canvas’ state via the View or Display menu. There should be a new item in there after the display has gone into ultra-paranoid mode. But save your file first if you made changes.