Make split-window inside a floating pane work more nicely and not

immediately create an overlapping pane, from Dane Jensen.

tmux.1

@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.1132 2026/07/10 15:20:06 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.1133 2026/07/13 10:03:27 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -14,7 +14,7 @@
 .\" IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 .\" OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 10 2026 $
+.Dd $Mdocdate: July 13 2026 $
 .Dt TMUX 1
 .Os
 .Sh NAME
@@ -4075,6 +4075,21 @@ or full window width (with
 .Fl v ) ,
 instead of splitting the active pane.
 .Pp
+If
+.Ar target\-pane
+is floating, a new floating pane is created adjacent to
+.Ar target\-pane
+with equal sizes.
+The position is determined by the
+.Fl h ,
+.Fl v ,
+and
+.Fl b
+flags.
+If any of the new pane would not be visible on the screen,
+.Ar target\-pane
+and the new pane are resized to fit.
+.Pp
 .Fl k
 keeps the pane open after the optional
 .Ar shell\-command