I need the page to bring this option checked by default in loading the page, but even putting the same check comes in white.
Note that the other field, has a similar structure and comes checked when loading the page.
<tr>
<td></td><td>
<input type="checkbox" name="optInventory"
{if $gui->projectOptions->inventoryEnabled} checked="checked" {/if} />
{$labels.testproject_enable_inventory}
</td>
</tr>
This is checked by default when loading the page:
<tr>
<td></td><td>
<input type="checkbox" name="is_public" {if $gui->is_public eq 1} checked="checked" {/if} />
{$labels.public}
</td>
</tr>
Output the option value to see if it is really what you expect. Also, I think that Smarty (at least some older versions) don't allow multiple use of ->
in an expression. Try to first assign the options to a template variable and then use that in your checkbox:
{assign var=opts value=$gui->projectOptions}
<input type="checkbox" {if $opts->inventoryEnabled}checked="checked"{/if} />