ShowDVI<#32#><#32#> should be always called from the CLI. Though start from the Workbench is possible, it is not further supported. But this is not tragical though, as TEXitself can only be started from the CLI too, which makes the CLI indispensable anyway.
For that there is a multitude of command line options. The call format looks like this:
<#502#>showdvi [-?] [-a <#33#>fontarea<#33#>] [-b <#34#>byte<#34#>] [-f <#35#>page<#35#>] [-z <#36#>dpi<#36#>] [-l] [-s] [-h <#37#>offset<#37#>] [-v <#38#>offset<#38#>] [-p] <#39#>dvifile<#39#><#502#> and offset = real number<#40#>{pt|pc|in|bp|cm|mm|dd|cc}<#40#>
<#41#>-h nxx <#41#>
<#42#>-?<#42#> Displays a short explanation of the options, without starting
the program.
<#43#>-a<#43#> Inserts an additional directory in the search path of the
fontlibraries and the PK-directories. For more see chapter 7.2.
<#44#>-b<#44#> Size of the memory range, in which loaded fonts are kept.
The display is in bytes. The default value can be displayed with the
<#45#>-?<#45#> option.
<#46#>-f n<#46#> Starts the display at page <#47#>n<#47#>.
<#48#>-z n<#48#> Overrides the default resolution and sets the value to
<#49#>n<#49#> dpi instead. The default resolution is 100 dpi.
<#50#>-h rxx<#50#> Sets the horizontal offset to <#51#>r<#51#>. <#52#>xx<#52#> is the unit.
These are the units you can choose from:
<#53#>;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;mm <#53#>
<#54#>;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;pt<#54#> point (is used by TEX<#55#><#55#>)
<#56#>;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;pc<#56#> pica