Docs: add a few notes and warnings (#2925)

* update docs.

* Update Xwayland.md.

* Apply suggestion from @YaLTeR

---------

Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

docs/wiki/Application-Issues.md

@@ -22,6 +22,12 @@ If you're having issues with some VSCode hotkeys, try starting `Xwayland` and se
 That is, still running VSCode with the Wayland backend, but with `DISPLAY` set to a running Xwayland instance.
 Apparently, VSCode currently unconditionally queries the X server for a keymap.
 
+### JetBrains IDEs
+
+JetBrains IDEs can run directly on Wayland, but it's not the default.
+
+For JetBrainsRuntime > 17, you can set the flag `-Dawt.toolkit.name=WLToolkit` inside of `help -> edit custom vm options -> add`.
+
 ### WezTerm
 
 > [!NOTE]

docs/wiki/Configuration:-Switch-Events.md

@@ -39,6 +39,9 @@ switch-events {
 These events trigger when a convertible laptop goes into or out of tablet mode.
 In tablet mode, the keyboard and mouse are usually inaccessible, so you can use these events to activate the on-screen keyboard.
 
+> [!NOTE]
+> The commands below are just examples, you will need to provide your own on-screen keyboard, such as [sysboard](https://github.com/System64fumo/sysboard) or [wvkbd](https://github.com/jjsullivan5196/wvkbd).
+
 ```kdl
 switch-events {
     tablet-mode-on { spawn "bash" "-c" "gsettings set org.gnome.desktop.a11y.applications screen-keyboard-enabled true"; }

docs/wiki/Important-Software.md

@@ -26,6 +26,9 @@ Note that if you're using the provided `resources/niri-portals.conf`, you also n
 
 If you do not want to install `nautilus` (say you use `nemo` instead), you can set `org.freedesktop.impl.portal.FileChooser=gtk;` in `niri-portals.conf` to use the GTK portal for file chooser dialogues.
 
+> [!WARNING]
+> Do not set the `GDK_BACKEND` environment variable globally as this will break the screencast portal.
+
 ### Authentication Agent
 
 Required when apps need to ask for root permissions. Something like `plasma-polkit-agent` works fine. Start it [with systemd](./Example-systemd-Setup.md) or with [`spawn-at-startup`](./Configuration:-Miscellaneous.md#spawn-at-startup).