Restore user's UI options when switching tabs

[jbarap]

Currently, if the user has opts.hide.statusline or opts.hide.tabline enabled, as long as a dashboard buffer exists, the user's UI components will stay hidden.

This results in the following workflow behaving strangely:

1. Open neovim to show dashboard
   • If you chose to hide tabline/statusline, they will be hidden to get a clean look
2. Run a command that creates a new tab (e.g. "DiffViewOpen"), or create a tab yourself
3. Watch as contents are filled in the new tab, but you still have your tabline/statusline hidden

This PR stores the user's UI preferences when starting a dashboard, and restores the user's UI settings every time he/she switches to a tab where there's no dashboard buffer visible.

Before (no tabline/statusline after running DiffViewFileHistory):

After (the expected tabline/statusline load when dashboard isn't visible):

Feel free to close the PR if you have a nicer solution in mind or if you find edge cases with this approach.

[folke]

The result of this PR is now exactly what you're trying to prevent for LazyVim and others.
We're now no longer seeing the statusline after exiting the dashboard.

[glepnir]

oh ..i don't look it carefully revert then.

[jbarap]

@folke can you elaborate? I'd like to find a way to change this behavior without breaking stuff and It'd be helpful to know how LazyVim breaks.

[folke]

In LazyVim we have hide.statusline = false, so hiding is disabled. We did that because it caused issues when opening a file from the cmdline.

See https://github.com/LazyVim/LazyVim/blob/ae381c91a1ec420cce082443501bace1ac7aaa3f/lua/lazyvim/plugins/ui.lua#L357

And

https://github.com/LazyVim/LazyVim/blob/ae381c91a1ec420cce082443501bace1ac7aaa3f/lua/lazyvim/plugins/ui.lua#L113-L129

[folke]

So for our use-case there's just nothing that should be restored?

[folke]

In LazyVim, lualine does already load, but we added dashboard to disabled filetypes.
vim.o.laststatus = 3 still.

So again, I think the problem with this PR is that settings are supposedly restored, while I explicitely tell dashboard to not touch my statusline.

[jbarap]

Got it. I missed the check for the setting before attempting to restore the settings, sorry for breaking LazyVim! Can you check if #458 solves it?

[folke]

Yep, all good now!