Fix sliders in effect editor not being precisely movable

files/mygui/openmw_edit_effect.layout

@@ -33,6 +33,7 @@
             </Widget>
             <Widget type="MWScrollBar" skin="MW_HScroll" position="122 20 210 13" name="MagnitudeMinSlider">
                 <Property key="Range" value="100"/>
+                <Property key="Page" value="1"/>
             </Widget>
 
             <Widget type="TextBox" skin="SandText" position="122 32 210 20" name="MagnitudeMaxValue">
@@ -41,6 +42,7 @@
             </Widget>
             <Widget type="MWScrollBar" skin="MW_HScroll" position="122 52 210 13" name="MagnitudeMaxSlider">
                 <Property key="Range" value="100"/>
+                <Property key="Page" value="1"/>
             </Widget>
         </Widget>
 
@@ -58,6 +60,7 @@
             </Widget>
             <Widget type="MWScrollBar" skin="MW_HScroll" position="122 20 210 13" name="DurationSlider">
                 <Property key="Range" value="1440"/>
+                <Property key="Page" value="1"/>
             </Widget>
         </Widget>
 
@@ -74,6 +77,7 @@
             </Widget>
             <Widget type="MWScrollBar" skin="MW_HScroll" position="122 20 210 13" name="AreaSlider">
                 <Property key="Range" value="51"/>
+                <Property key="Page" value="1"/>
             </Widget>
         </Widget>