Relax size constraints on mul entry box

The given fixed size is far too small. Removing the maximum size and
allowing it adjust to its preferred size should fix this problem.

qrenderdoc/Windows/TextureViewer.ui

@@ -608,7 +608,7 @@
     <item>
      <widget class="QComboBox" name="comboBox_5">
       <property name="sizePolicy">
-       <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
+       <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
         <horstretch>0</horstretch>
         <verstretch>0</verstretch>
        </sizepolicy>
@@ -621,7 +621,7 @@
       </property>
       <property name="maximumSize">
        <size>
-        <width>50</width>
+        <width>16777215</width>
         <height>16777215</height>
        </size>
       </property>