Hi,
Add the following lines in view.xsl. Search with the button id. You will find some thing like
<input class="langFont" title="" type="button" xd:CtrlId="CTRL1_5" xd:xctname="Button" tabIndex="0" value="Button">
Replace the above line with the following.
<input class="langFont" title="" type="button" xd:CtrlId="CTRL1_5" xd:xctname="Button" tabIndex="0">
<xsl:attribute name="value">
<xsl:value-of select="my:field1"/>
</xsl:attribute>
</input>
Here my:field1 is the drop down field xpath.
Note: Make sure to have a back up file before doing this.