diff --git a/bar/bar.c b/bar/bar.c
index 21d95c5..b29936b 100644
--- a/bar/bar.c
+++ b/bar/bar.c
@@ -55,9 +55,16 @@ calculate_widths(const struct private *b, int *left, int *center, int *right)
     }
 
     /* No spacing on the edges (that's what the margins are for) */
-    *left -= b->left_spacing + b->right_spacing;
-    *center -= b->left_spacing + b->right_spacing;
-    *right -= b->left_spacing + b->right_spacing;
+    if (*left > 0)
+        *left -= b->left_spacing + b->right_spacing;
+    if (*center > 0)
+        *center -= b->left_spacing + b->right_spacing;
+    if (*right > 0)
+        *right -= b->left_spacing + b->right_spacing;
+
+    assert(*left >= 0);
+    assert(*center >= 0);
+    assert(*right >= 0);
 }
 
 static void
@@ -99,6 +106,7 @@ expose(const struct bar *_bar)
         if (e != NULL)
             e->destroy(e);
         bar->left.exps[i] = module_begin_expose(m);
+        assert(bar->left.exps[i]->width >= 0);
     }
 
     for (size_t i = 0; i < bar->center.count; i++) {
@@ -107,6 +115,7 @@ expose(const struct bar *_bar)
         if (e != NULL)
             e->destroy(e);
         bar->center.exps[i] = module_begin_expose(m);
+        assert(bar->center.exps[i]->width >= 0);
     }
 
     for (size_t i = 0; i < bar->right.count; i++) {
@@ -115,6 +124,7 @@ expose(const struct bar *_bar)
         if (e != NULL)
             e->destroy(e);
         bar->right.exps[i] = module_begin_expose(m);
+        assert(bar->right.exps[i]->width >= 0);
     }
 
     int left_width, center_width, right_width;
@@ -196,7 +206,8 @@ on_mouse(struct bar *_bar, enum mouse_event event, enum mouse_button btn,
     for (size_t i = 0; i < bar->left.count; i++) {
         struct exposable *e = bar->left.exps[i];
 
-        if (e->width == 0) continue;
+        if (e->width == 0)
+            continue;
 
         mx += bar->left_spacing;
         if (x >= mx && x < mx + e->width) {
@@ -212,7 +223,8 @@ on_mouse(struct bar *_bar, enum mouse_event event, enum mouse_button btn,
     for (size_t i = 0; i < bar->center.count; i++) {
         struct exposable *e = bar->center.exps[i];
 
-        if (e->width == 0) continue;
+        if (e->width == 0)
+            continue;
 
         mx += bar->left_spacing;
         if (x >= mx && x < mx + e->width) {
@@ -224,15 +236,16 @@ on_mouse(struct bar *_bar, enum mouse_event event, enum mouse_button btn,
         mx += e->width + bar->right_spacing;
     }
 
-    mx = bar->width - (right_width
-                       + bar->left_spacing +
+    mx = bar->width - (right_width +
+                       bar->left_spacing +
                        bar->right_margin +
                        bar->border.right_width);
 
     for (size_t i = 0; i < bar->right.count; i++) {
         struct exposable *e = bar->right.exps[i];
 
-        if (e->width == 0) continue;
+        if (e->width == 0)
+            continue;
 
         mx += bar->left_spacing;
         if (x >= mx && x < mx + e->width) {
diff --git a/particles/dynlist.c b/particles/dynlist.c
index 8c6319c..5b64dbe 100644
--- a/particles/dynlist.c
+++ b/particles/dynlist.c
@@ -1,6 +1,7 @@
 #include "dynlist.h"
 
 #include <stdlib.h>
+#include <assert.h>
 
 #define LOG_MODULE "dynlist"
 #include "../log.h"
@@ -36,15 +37,24 @@ dynlist_begin_expose(struct exposable *exposable)
     const struct private *e = exposable->private;
 
     exposable->width = 0;
+    bool have_at_least_one = false;
 
     for (size_t i = 0; i < e->count; i++) {
         struct exposable *ee = e->exposables[i];
         e->widths[i] = ee->begin_expose(ee);
 
-        exposable->width += e->left_spacing + e->widths[i] + e->right_spacing;
+        assert(e->widths[i] >= 0);
+
+        if (e->widths[i] > 0) {
+            exposable->width += e->left_spacing + e->widths[i] + e->right_spacing;
+            have_at_least_one = true;
+        }
     }
 
-    exposable->width -= e->left_spacing + e->right_spacing;
+    if (have_at_least_one)
+        exposable->width -= e->left_spacing + e->right_spacing;
+    else
+        assert(exposable->width == 0);
     return exposable->width;
 }
 
diff --git a/particles/list.c b/particles/list.c
index 9f03231..19ff15b 100644
--- a/particles/list.c
+++ b/particles/list.c
@@ -39,18 +39,29 @@ static int
 begin_expose(struct exposable *exposable)
 {
     const struct eprivate *e = exposable->private;
+    bool have_at_least_one = false;
 
-    exposable->width = exposable->particle->left_margin;
+    exposable->width = 0;
 
     for (size_t i = 0; i < e->count; i++) {
         struct exposable *ee = e->exposables[i];
         e->widths[i] = ee->begin_expose(ee);
 
-        exposable->width += e->left_spacing + e->widths[i] + e->right_spacing;
+        assert(e->widths[i] >= 0);
+
+        if (e->widths[i] > 0) {
+            exposable->width += e->left_spacing + e->widths[i] + e->right_spacing;
+            have_at_least_one = true;
+        }
     }
 
-    exposable->width -= e->left_spacing + e->right_spacing;
-    exposable->width += exposable->particle->right_margin;
+    if (have_at_least_one) {
+        exposable->width -= e->left_spacing + e->right_spacing;
+        exposable->width += exposable->particle->left_margin;
+        exposable->width += exposable->particle->right_margin;
+    } else
+        assert(exposable->width == 0);
+
     return exposable->width;
 }
 
diff --git a/particles/map.c b/particles/map.c
index e2d8c03..980bdd1 100644
--- a/particles/map.c
+++ b/particles/map.c
@@ -41,11 +41,13 @@ begin_expose(struct exposable *exposable)
 {
     struct eprivate *e = exposable->private;
 
-    exposable->width = (
-        exposable->particle->left_margin +
-        e->exposable->begin_expose(e->exposable) +
-        exposable->particle->right_margin);
+    int width = e->exposable->begin_expose(e->exposable);
+    assert(width >= 0);
 
+    if (width > 0)
+        width += exposable->particle->left_margin + exposable->particle->right_margin;
+
+    exposable->width = width;
     return exposable->width;
 }
 
diff --git a/particles/progress-bar.c b/particles/progress-bar.c
index 52d1e74..7011feb 100644
--- a/particles/progress-bar.c
+++ b/particles/progress-bar.c
@@ -57,14 +57,27 @@ static int
 begin_expose(struct exposable *exposable)
 {
     struct eprivate *e = exposable->private;
+    bool have_at_least_one = false;
 
-    /* Margins */
-    exposable->width = exposable->particle->left_margin +
-        exposable->particle->right_margin;
+    exposable->width = 0;
 
     /* Sub-exposables */
-    for (size_t i = 0; i < e->count; i++)
-        exposable->width += e->exposables[i]->begin_expose(e->exposables[i]);
+    for (size_t i = 0; i < e->count; i++) {
+        int width = e->exposables[i]->begin_expose(e->exposables[i]);
+
+        assert(width >= 0);
+        if (width >= 0) {
+            exposable->width += width;
+            have_at_least_one = true;
+        }
+    }
+
+    /* Margins */
+    if (have_at_least_one) {
+        exposable->width = exposable->particle->left_margin +
+            exposable->particle->right_margin;
+    } else
+        assert(exposable->width == 0);
 
     return exposable->width;
 }
diff --git a/particles/ramp.c b/particles/ramp.c
index 3fa2fc8..1d4cb59 100644
--- a/particles/ramp.c
+++ b/particles/ramp.c
@@ -37,11 +37,13 @@ begin_expose(struct exposable *exposable)
 {
     struct eprivate *e = exposable->private;
 
-    exposable->width = (
-        exposable->particle->left_margin +
-        e->exposable->begin_expose(e->exposable) +
-        exposable->particle->right_margin);
+    int width = e->exposable->begin_expose(e->exposable);
+    assert(width >= 0);
 
+    if (width > 0)
+        width += exposable->particle->left_margin + exposable->particle->right_margin;
+
+    exposable->width = width;
     return exposable->width;
 }