diff --git a/library/lua/gui.lua b/library/lua/gui.lua
index ce228d715..709ff65f9 100644
--- a/library/lua/gui.lua
+++ b/library/lua/gui.lua
@@ -11,7 +11,7 @@ USE_GRAPHICS = dscreen.inGraphicsMode()
 
 local to_pen = dfhack.pen.parse
 
-CLEAR_PEN = to_pen{ch=32,fg=0,bg=0}
+CLEAR_PEN = to_pen{tile=909, ch=32, fg=0, bg=0}
 
 local FAKE_INPUT_KEYS = {
     _MOUSE_L = true,
@@ -624,6 +624,7 @@ function Screen:renderParent()
     else
         dscreen.clear()
     end
+    df.global.gps.force_full_display_count = 1
 end
 
 function Screen:sendInputToParent(...)
@@ -693,15 +694,17 @@ BOUNDARY_FRAME = {
 }
 
 GREY_LINE_FRAME = {
-    frame_pen = to_pen{ ch = 206, fg = COLOR_GREY, bg = COLOR_BLACK },
-    h_frame_pen = to_pen{ ch = 205, fg = COLOR_GREY, bg = COLOR_BLACK },
-    v_frame_pen = to_pen{ ch = 186, fg = COLOR_GREY, bg = COLOR_BLACK },
-    lt_frame_pen = to_pen{ ch = 201, fg = COLOR_GREY, bg = COLOR_BLACK },
-    lb_frame_pen = to_pen{ ch = 200, fg = COLOR_GREY, bg = COLOR_BLACK },
-    rt_frame_pen = to_pen{ ch = 187, fg = COLOR_GREY, bg = COLOR_BLACK },
-    rb_frame_pen = to_pen{ ch = 188, fg = COLOR_GREY, bg = COLOR_BLACK },
-    title_pen = to_pen{ fg = COLOR_BLACK, bg = COLOR_GREY },
-    signature_pen = to_pen{ fg = COLOR_GREY, bg = COLOR_BLACK },
+    frame_pen = to_pen{ ch=206, fg=COLOR_GREY, bg=COLOR_BLACK },
+    t_frame_pen = to_pen{ tile=902, ch=205, fg=COLOR_GREY, bg=COLOR_BLACK },
+    l_frame_pen = to_pen{ tile=908, ch=186, fg=COLOR_GREY, bg=COLOR_BLACK },
+    b_frame_pen = to_pen{ tile=916, ch=205, fg=COLOR_GREY, bg=COLOR_BLACK },
+    r_frame_pen = to_pen{ tile=910, ch=186, fg=COLOR_GREY, bg=COLOR_BLACK },
+    lt_frame_pen = to_pen{ tile=901, ch=201, fg=COLOR_GREY, bg=COLOR_BLACK },
+    lb_frame_pen = to_pen{ tile=915, ch=200, fg=COLOR_GREY, bg=COLOR_BLACK },
+    rt_frame_pen = to_pen{ tile=903, ch=187, fg=COLOR_GREY, bg=COLOR_BLACK },
+    rb_frame_pen = to_pen{ tile=917, ch=188, fg=COLOR_GREY, bg=COLOR_BLACK },
+    title_pen = to_pen{ fg=COLOR_BLACK, bg=COLOR_GREY },
+    signature_pen = to_pen{ fg=COLOR_GREY, bg=COLOR_BLACK },
 }
 
 function paint_frame(dc,rect,style,title)
diff --git a/library/modules/Screen.cpp b/library/modules/Screen.cpp
index 5baadb052..653ab0bd3 100644
--- a/library/modules/Screen.cpp
+++ b/library/modules/Screen.cpp
@@ -54,7 +54,7 @@ using namespace DFHack;
 #include "df/tile_pagest.h"
 #include "df/interfacest.h"
 #include "df/enabler.h"
-#include "df/graphic_map_portst.h"
+#include "df/graphic_viewportst.h"
 #include "df/unit.h"
 #include "df/item.h"
 #include "df/job.h"
@@ -115,39 +115,72 @@ bool Screen::inGraphicsMode()
     return init && init->display.flag.is_set(init_display_flags::USE_GRAPHICS);
 }
 
+static bool doSetTile_map(const Pen &pen, int x, int y) {
+    size_t index = (x * gps->main_viewport->dim_y) + y;
+    long texpos = pen.tile;
+    if (texpos == 0) {
+        texpos = init->font.large_font_texpos[(uint8_t)pen.ch];
+    }
+    gps->main_viewport->screentexpos_interface[index] = texpos;
+    return true;
+}
+
 static bool doSetTile_default(const Pen &pen, int x, int y, bool map)
 {
-// TODO: understand how this changes for v50
-    size_t index = ((x * gps->dimy) + y);
-    if (!map) {
-        // don't let DF overlay interface elements draw over us
-        gps->screentexpos_anchored[index] = 0;
-        gps->screentexpos_top[index] = 0;
-        gps->screentexpos_flag[index] = 0;
+    bool use_graphics = Screen::inGraphicsMode();
+
+    if (map && use_graphics)
+        return doSetTile_map(pen, x, y);
+
+    size_t index = (x * gps->dimy) + y;
+    uint8_t *screen = &gps->screen[index * 8];
+
+    if (screen > gps->screen_limit)
+        return false;
+
+    long *texpos = &gps->screentexpos[index];
+    long *texpos_lower = &gps->screentexpos_lower[index];
+    uint32_t *flag = &gps->screentexpos_flag[index];
+
+    *screen = 0;
+    *texpos = 0;
+    *texpos_lower = 0;
+    *flag = 4; // remove SCREENTEXPOS_FLAG_ANCHOR_SUBORDINATE
+
+    if (gps->top_in_use) {
+        screen = &gps->screen_top[index * 8];
+        texpos = &gps->screentexpos_top[index];
+        texpos_lower = &gps->screentexpos_top_lower[index];
+        flag = &gps->screentexpos_top_flag[index];
+
+        *screen = 0;
+        *texpos = 0;
+        *texpos_lower = 0;
+        *flag = 4; // remove SCREENTEXPOS_FLAG_ANCHOR_SUBORDINATE
+    }
+
+    if (pen.tile_mode == Screen::Pen::CharColor)
+        *flag |= 2; // SCREENTEXPOS_FLAG_ADDCOLOR
+    else if (pen.tile_mode == Screen::Pen::TileColor)
+        *flag |= 1; // SCREENTEXPOS_FLAG_GRAYSCALE
+
+    if (pen.tile && use_graphics) {
+        *texpos = pen.tile;
+    } else {
+        screen[0] = uint8_t(pen.ch);
+        *texpos_lower = 909;
     }
-    //gps->screen1_opt_tile[index] = uint8_t(pen.tile);
+
+    // note that pen.bold currently (50.04) has no representation in the DF data
     auto fg = &gps->uccolor[pen.fg][0];
     auto bg = &gps->uccolor[pen.bg][0];
-    auto argb = &gps->screen[index * 8];
-    argb[0] = uint8_t(pen.ch);
-    argb[1] = fg[0];
-    argb[2] = fg[1];
-    argb[3] = fg[2];
-    argb[4] = bg[0];
-    argb[5] = bg[1];
-    argb[6] = bg[2];
-/* old code
-//     auto screen = gps->screen + index*4;
-//     screen[0] = uint8_t(pen.ch);
-//     screen[1] = uint8_t(pen.fg) & 15;
-//     screen[2] = uint8_t(pen.bg) & 15;
-//     screen[3] = uint8_t(pen.bold) & 1;
-//     gps->screentexpos[index] = pen.tile;
-//     gps->screentexpos_addcolor[index] = (pen.tile_mode == Screen::Pen::CharColor);
-//     gps->screentexpos_grayscale[index] = (pen.tile_mode == Screen::Pen::TileColor);
-//     gps->screentexpos_cf[index] = pen.tile_fg;
-//     gps->screentexpos_cbr[index] = pen.tile_bg;
-*/
+    screen[1] = fg[0];
+    screen[2] = fg[1];
+    screen[3] = fg[2];
+    screen[4] = bg[0];
+    screen[5] = bg[1];
+    screen[6] = bg[2];
+
     return true;
 }