Hi vaclav,
To remove this dot, edit the view "product / show_block_dimension.php" in HikaShop > Display > Views.
And add a dot before '0' in the first rtrim(), like this:
<?php echo JText::_('PRODUCT_WIDTH').': '.rtrim(rtrim($this->element->product_width,',.'),'0').' '.JText::_($this->element->product_dimension_unit); ?><br />
To:
<?php echo JText::_('PRODUCT_WIDTH').': '.rtrim(rtrim($this->element->product_width,',.'),'.0').' '.JText::_($this->element->product_dimension_unit); ?><br />
For each dimensions properties.