Fix percents when attaching a window to a ws creates a new split con

Fixes #1484 and includes a test case.

src/workspace.c

@@ -846,6 +846,9 @@ Con *workspace_attach_to(Con *ws) {
     DLOG("Attaching new split %p to workspace %p\n", new, ws);
     con_attach(new, ws, false);
 
+    /* 5: fix the percentages */
+    con_fix_percent(ws);
+
     return new;
 }
 

testcases/t/240-tabbed-floating-disable-crash.t

@@ -0,0 +1,44 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Verifies that i3 does not crash when floating and then unfloating an
+# unfocused window within a tabbed container.
+# Ticket: #1484
+# Bug still in: 4.9.1-124-g856e1f9
+use i3test i3_autostart => 0;
+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+workspace_layout tabbed
+EOT
+
+my $pid = launch_with_config($config);
+
+open_window;
+open_window;
+
+# Mark the second window, then focus the workspace.
+cmd 'mark foo, focus parent, focus parent';
+
+# Float and unfloat the marked window (without it being focused).
+cmd '[con_mark=foo] floating enable, floating disable';
+
+does_i3_live;
+
+exit_gracefully($pid);
+
+done_testing;