I ve been using Tweaks to add apps, and all have worked but one, (Guake Terminal,) will not stick. Every boot it is somehow removed. Are there other ways to add an app to startup? I m running Gnome DE.
I checked dconf, and noticed that quake has it s own entry, and after looking at the various settings, there is one for starting at boot. Probably explains why it is getting removed.
Why not easy?
If you haven’t yet then install gnome-tweaks. Start it and go to Startup Applications
My first post states that tweaks did not work, but the problem was fixed by using dconf as it shows in my subsequent posts 
Of course, tweaks works fine.
Please be more specific for which app tweaks did not work.
I see, you mentioned Guake. Sorry for my bad reading.
This is easy. Guake and also Keepassxc have in their settings the startup at login.
Let’s assume you have added Guake in tweaks startup applications. If you don’t have it in the Guake settings then Guake turns automatic start off.
Here is what you need.
