diff --git a/CHANGELOG.md b/CHANGELOG.md
index aecbc12..8cdc51a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 #### Added
 - add menu time_lapse for changing the simulation/ replay speed
 - add field `mod_text` to Viewer3D; it defines the quotient of the update rate and the text update rate
+- add textbox `t_sim` to enter the simulation time
 
 ### KiteViewers v0.4.10 - 2024-03-30
 
diff --git a/mwes/mwe_05.jl b/mwes/mwe_05.jl
index 570a24b..2a3bd63 100644
--- a/mwes/mwe_05.jl
+++ b/mwes/mwe_05.jl
@@ -5,4 +5,4 @@ segments=se().segments
 state=demo_state_4p(segments+1)
 update_system(viewer, state, kite_scale=0.25)
 sleep(5)
-close(viewer.screen)
\ No newline at end of file
+#close(viewer.screen)
\ No newline at end of file
diff --git a/src/viewer3D.jl b/src/viewer3D.jl
index 5c3e031..2151a04 100644
--- a/src/viewer3D.jl
+++ b/src/viewer3D.jl
@@ -85,6 +85,7 @@ mutable struct Viewer3D <: AKV
     menu::Union{Menu, Nothing}
     menu_rel_tol::Union{Menu, Nothing}
     menu_time_lapse::Union{Menu, Nothing}
+    t_sim::Union{Textbox, Nothing}
     btn_OK::Union{Button, Nothing}
     sw::Toggle
     step::Int64
@@ -158,6 +159,17 @@ function Viewer3D(set::Settings, show_kite=true, autolabel="Autopilot"; precompi
         label3.halign[]=:left
         label3.valign[]=:top
         label3.alignmode=Outside(160, 0, 0, 100)
+        tb = Textbox(fig, bbox = fig.scene.viewport, placeholder = "Simulation time",
+                     validator = UInt16, stored_string="460")
+        tb.width[] =120
+        tb.halign[]=:left
+        tb.valign[]=:top
+        tb.alignmode[]=Outside(30, 0, 0, 130)
+        # tb.stored_string[]="460"
+        label3 = Label(fig, "t_sim [s]", bbox=fig.scene.viewport)
+        label3.halign[]=:left
+        label3.valign[]=:top
+        label3.alignmode=Outside(160, 0, 0, 137)
         btn_OK         = Button(fig, bbox=fig.scene.viewport, label = "OK")
         btn_OK.halign[]=:left
         btn_OK.valign[]=:top
@@ -166,6 +178,7 @@ function Viewer3D(set::Settings, show_kite=true, autolabel="Autopilot"; precompi
         menu1=nothing
         menu2=nothing
         menu3=nothing
+        tb = nothing
         btn_OK=nothing
     end
 
@@ -229,7 +242,7 @@ function Viewer3D(set::Settings, show_kite=true, autolabel="Autopilot"; precompi
     mod_text = 4
     s = Viewer3D(fig, scene3D, cam, gl_screen, points, pos, part_pos, markersizes, 
                  rotations, set, btn_RESET, btn_ZOOM_in, btn_ZOOM_out, 
-                 btn_PLAY_PAUSE, btn_AUTO, btn_PARKING, btn_STOP, menu1, menu2, menu3, btn_OK,
+                 btn_PLAY_PAUSE, btn_AUTO, btn_PARKING, btn_STOP, menu1, menu2, menu3, tb, btn_OK,
                  sw, 0, mod_text, 0, show_kite, false)
     txt2 = init_system(s, s.scene3D; show_kite=show_kite)