I have Mellel 2.1.1 installed on an Intel MacBook and keep encountering similar slowness.
Mellel will open quickly when double-clicked; however, if it opens by double-clicking a Mellel document or if you Open a Mellel document from within Mellel, you get the spinning beachball for a few minutes. The spinning beachball appears when savings files too, but not always. After a couple saves of the same document, Mellel sometimes shifts into normal speed on that particular document; however, if you quit Mellel then open that document again, the slowness returns.
For what it's worth, I did experience this slowness before v2. Mellel 1.9.1 and its predecessors were speedy!
Since I haven't done so yet, I will try deleting preferences, checking fonts, and such.
Problems with Mellel
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