Disallow OSC 52 for unfocused window

This leads to issues on macOS, since if we store clipboard at the same
time it could error out. Also, on e.g. Wayland the clipboard store for
unfocused window won't work anyway.

CHANGELOG.md

@@ -23,6 +23,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed
 
 - The `--help` output was reworked with a new colorful syntax
+- OSC 52 is now disabled on unfocused windows
 
 ### Fixed
 

alacritty/src/event.rs

@@ -1078,11 +1078,15 @@ impl input::Processor<EventProxy, ActionContext<'_, Notifier, EventProxy>> {
                         }
                     },
                     TerminalEvent::ClipboardStore(clipboard_type, content) => {
-                        self.ctx.clipboard.store(clipboard_type, content);
+                        if self.ctx.terminal.is_focused {
+                            self.ctx.clipboard.store(clipboard_type, content);
+                        }
                     },
                     TerminalEvent::ClipboardLoad(clipboard_type, format) => {
-                        let text = format(self.ctx.clipboard.load(clipboard_type).as_str());
-                        self.ctx.write_to_pty(text.into_bytes());
+                        if self.ctx.terminal.is_focused {
+                            let text = format(self.ctx.clipboard.load(clipboard_type).as_str());
+                            self.ctx.write_to_pty(text.into_bytes());
+                        }
                     },
                     TerminalEvent::ColorRequest(index, format) => {
                         let color = self.ctx.terminal().colors()[index]