diff --git a/kdevplatform/sublime/ideallayout.cpp b/kdevplatform/sublime/ideallayout.cpp
--- a/kdevplatform/sublime/ideallayout.cpp
+++ b/kdevplatform/sublime/ideallayout.cpp
@@ -22,6 +22,8 @@
 
 #include "ideallayout.h"
 
+#include <debug.h>
+
 #include <QStyle>
 #include <QWidget>
 
@@ -72,19 +74,37 @@
 
 QSize IdealButtonBarLayout::minimumSize() const
 {
-    // The code below appears to be completely wrong --
-    // it will return the maximum size of a single button, not any
-    // estimate as to how much space is necessary to draw all buttons
-    // in a minimally acceptable way.
     if (m_minSizeDirty) {
-        if (orientation() == Qt::Vertical) {
-            const int width = doVerticalLayout(QRect(0, 0, 0, _height), false);
-            return QSize(width, 0);
-        }
+        const int buttonSpacing = this->buttonSpacing();
 
-        m_min = QSize(0, 0);
+        bool first = true;
+        int orientationSize = 0;
+        int crossSize = 0;
         for (QLayoutItem* item : _items) {
-            m_min = m_min.expandedTo(item->minimumSize());
+            const QSize itemMinSize = item->minimumSize();
+
+            int orientationSizeHere;
+            int crossSizeHere;
+            if (orientation() == Qt::Vertical) {
+                orientationSizeHere = itemMinSize.height();
+                crossSizeHere = itemMinSize.width();
+            } else {
+                orientationSizeHere = itemMinSize.width();
+                crossSizeHere = itemMinSize.height();
+            }
+
+            if (first) {
+                crossSize = crossSizeHere;
+                first = false;
+            } else {
+                orientationSize += buttonSpacing;
+            }
+            orientationSize += orientationSizeHere;
+        }
+        if (orientation() == Qt::Vertical) {
+            m_min = QSize(crossSize, orientationSize);
+        } else {
+            m_min = QSize(orientationSize, crossSize);
         }
 
         m_minSizeDirty = false;
@@ -202,9 +222,10 @@
         return x + currentLineWidth + r;
     }
 
-    const bool shrink = rect.height() < sizeHint().height();
+    bool shrink = rect.height() < sizeHint().height();
 
-    const int maximumHeight = rect.height() / _items.size();
+    // space left per button after removing available space for buttonSpacing
+    const int maximumHeight = (rect.height() - buttonSpacing * (_items.size() - 1)) / _items.size();
     int shrinkedHeight = -1;
 
     if (shrink) {
@@ -218,9 +239,14 @@
             return acc;
         });
 
-        Q_ASSERT(_items.size() != smallItemCount); // should be true since rect.width != sizeHint.width
-        // evenly distribute surplus height over large items
-        shrinkedHeight = maximumHeight + surplus / (_items.size() - smallItemCount);
+        // Sanity check to prevent against a divide-by-zero due to some latent miscalculations
+        if (_items.size() != smallItemCount) {
+            // evenly distribute surplus height over large items
+            shrinkedHeight = maximumHeight + surplus / (_items.size() - smallItemCount);
+        } else {
+            qCDebug(SUBLIME) << "Expected at least one large item, none found, possible erraneous shrink predicate or sizeHint";
+            shrink = false;
+        }
     }
 
     for (QLayoutItem* item : _items) {
@@ -260,9 +286,10 @@
         return y + currentLineHeight + b;
     }
 
-    const bool shrink = rect.width() < sizeHint().width();
+    bool shrink = rect.width() < sizeHint().width();
 
-    const int maximumWidth = rect.width() / _items.size();
+    // space left per button after removing available space for buttonSpacing
+    const int maximumWidth = (rect.width() - buttonSpacing * (_items.size() - 1)) / _items.size();
     int shrinkedWidth = -1;
 
     if (shrink) {
@@ -276,9 +303,14 @@
             return acc;
         });
 
-        Q_ASSERT(_items.size() != smallItemCount); // should be true since rect.width != sizeHint.width
-        // evenly distribute surplus width on the large items
-        shrinkedWidth = maximumWidth + surplus / (_items.size() - smallItemCount);
+        // Sanity check to prevent against a divide-by-zero due to some latent miscalculations
+        if (_items.size() != smallItemCount) {
+            // evenly distribute surplus width on the large items
+            shrinkedWidth = maximumWidth + surplus / (_items.size() - smallItemCount);
+        } else {
+            qCDebug(SUBLIME) << "Expected at least one large item, none found, possible erraneous shrink predicate or sizeHint";
+            shrink = false;
+        }
     }
 
     for (QLayoutItem* item : _items) {
diff --git a/kdevplatform/sublime/idealtoolbutton.h b/kdevplatform/sublime/idealtoolbutton.h
--- a/kdevplatform/sublime/idealtoolbutton.h
+++ b/kdevplatform/sublime/idealtoolbutton.h
@@ -36,6 +36,8 @@
 
     QSize sizeHint() const override;
 
+    QSize minimumSizeHint() const override;
+
 protected:
     void paintEvent(QPaintEvent *event) override;
 
diff --git a/kdevplatform/sublime/idealtoolbutton.cpp b/kdevplatform/sublime/idealtoolbutton.cpp
--- a/kdevplatform/sublime/idealtoolbutton.cpp
+++ b/kdevplatform/sublime/idealtoolbutton.cpp
@@ -35,6 +35,14 @@
     setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
 
     setContextMenuPolicy(Qt::CustomContextMenu);
+
+    QSizePolicy sizePolicy = this->sizePolicy();
+    if (orientation() == Qt::Horizontal) {
+        sizePolicy.setHorizontalPolicy(QSizePolicy::Preferred);
+    } else {
+        sizePolicy.setVerticalPolicy(QSizePolicy::Preferred);
+    }
+    setSizePolicy(sizePolicy);
 }
 
 Qt::Orientation IdealToolButton::orientation() const
@@ -86,6 +94,37 @@
     }
 }
 
+QSize IdealToolButton::minimumSizeHint() const
+{
+    QStyleOptionToolButton opt;
+    initStyleOption(&opt);
+
+    // if style has icons, minimumSize is the size of the icon
+    if (toolButtonStyle() != Qt::ToolButtonTextOnly && !opt.icon.isNull()) {
+        int iconWidth = 0;
+        int iconHeight = 0;
+        if (_area == Qt::TopDockWidgetArea || _area == Qt::BottomDockWidgetArea) {
+            iconWidth = opt.iconSize.width();
+            iconHeight = opt.iconSize.height();
+        } else {
+            iconWidth = opt.iconSize.height();
+            iconHeight = opt.iconSize.width();
+        }
+
+        return {iconWidth + 1, iconHeight + 1};
+    } else {
+        // if no icon, set an arbitrary minimum size
+        QFontMetrics fm = fontMetrics();
+        const QSize minimumSize = fm.size(Qt::TextShowMnemonic, opt.text.left(4));
+        if (_area == Qt::TopDockWidgetArea || _area == Qt::BottomDockWidgetArea) {
+            return minimumSize;
+        } else {
+            return {minimumSize.height(), minimumSize.width()};
+        }
+    }
+}
+
+
 void IdealToolButton::paintEvent(QPaintEvent *event)
 {
     Q_UNUSED(event);