This one's been around since 5.0, and it's open to interpretation whether it constitutes a bug or a feature request, but in any case is something I think should be taken care of.
When there is a blank tab already open in the drawer (for whatever reason), and an external application tells OmniWeb to open a URL, instead of using the existing blank tab, another new tab is needlessly created, and then I have to close the first one. Since a blank tab is obviously not serving any purpose other than to eventually be used to load a page, I believe it can be safely assumed that a user wanted that tab to be used in the next situation where a new tab is needed.
Although this isn't necessarily the only situation in which it happens, I am in the habit of sometimes creating a new tab when I want to be sure that a link from another program will not replace any of my currently-open tabs. I do have OmniWeb set to open external links in a new tab, but the behavior of OmniWeb's search field in the toolbar is such that it isn't possible to start a search in a new tab without manually creating the new tab before searching (since Command-return still doesn't work in that field; this in itself should be added as well, but that's another story), and this inconsistency is the main reason why I sometimes end up creating new tabs in other situations where it's not necessary. In those cases -- or in any other situation where a new tab was created but not used for anything -- that tab should be used for anything that tries to create a new tab, rather than creating another new one.
When there is a blank tab already open in the drawer (for whatever reason), and an external application tells OmniWeb to open a URL, instead of using the existing blank tab, another new tab is needlessly created, and then I have to close the first one. Since a blank tab is obviously not serving any purpose other than to eventually be used to load a page, I believe it can be safely assumed that a user wanted that tab to be used in the next situation where a new tab is needed.
Although this isn't necessarily the only situation in which it happens, I am in the habit of sometimes creating a new tab when I want to be sure that a link from another program will not replace any of my currently-open tabs. I do have OmniWeb set to open external links in a new tab, but the behavior of OmniWeb's search field in the toolbar is such that it isn't possible to start a search in a new tab without manually creating the new tab before searching (since Command-return still doesn't work in that field; this in itself should be added as well, but that's another story), and this inconsistency is the main reason why I sometimes end up creating new tabs in other situations where it's not necessary. In those cases -- or in any other situation where a new tab was created but not used for anything -- that tab should be used for anything that tries to create a new tab, rather than creating another new one.