I just installed Blank Canvas v1.12.05b, but I can't get it to work in my primary Gmail account - i.e., the only one I actually want it to work in.  I have 3 gmail accounts, 2 of which I import into my primary gmail account.  Blank Canvas works in my two secondary accounts, but the Blank Canvas buttons and drop-down box do not appear when I compose a new email in my primary gmail account.

The first time I installed it, I was logged into a secondary email account, which I thought might be the cause.  So I uninstalled Blank Canvas, restarted Firefox, logged into my primary Gmail account, and reinstalled Blank Canvas.  But it still only works in my two secondary Gmail accounts.  I also uninstalled two Gmail-related add-ons, BetterGmail2 and GmailNotifier, but the problem still persists.

Here is the requested information:

• What version of BC Gmail Signatures are you using? v1.12.05b (I couldn't even install the default 1.11.09 version - it gave me an "unknown installation problem" error message)
• What version of Firefox are you using? v3.5.8
• Are you using regular Gmail or Google Apps? regular Gmail
• What version of Gmail do you have? ** gmail_fe_642_p26

• Do you have any Gmail Labs features enabled? no
• Do you have any "send as" addresses set up? yes, in my primary Gmail account I have "send as" addresses set up for all 3 gmail addresses.  In my secondary Gmail accounts, I do not have multiple "send as" addresses.  Though FYI, I tried deleting the additional "send as" addresses in my primary Gmail account and this did not solve the problem.
• What locale is your Firefox set to? (e.g. en-US, pt-BR, etc.) en-US
• What language is your Gmail account set to? English (US)
• What other add-ons do you have installed and enabled? Dog Ears 1.9, Download Statusbar 0.9.6.7, Forecastbar Enhanced 0.9.6, Gmail Space 0.5.995, Google Toolbar for Firefox 6.1.20091216W, LongURL Please 0.4.2, NoScript 1.9.9.47, Personas 1.5.1, ReadItLater 2.0.3, Xmarks 3.4.10, Zotero 1.0.10

Any advice or suggestions would be welcome!  I can't think of anything that's different between my primary Gmail account and my secondary accounts that would allow Blank Canvas to work in the secondaries but not the primary.  Ideas?

Jerome - thanks for the tips.  But I had already done both - googleapis.com is in my NoScript White List, and I had already set the BlankCanvas Debug options as you described.  Besides, I'm switching between Gmail accounts within the same browser window, and within a matter of seconds I will either get the BlankCanvas drop-down boxes in my secondary accounts or not get the BlankCanvas drop-down boxes in my primary account.  So it can't be a browser issue.

I've gone through all my settings and the only things that differed between my primary and my secondary accounts were that I had a theme set in my primary account, and also had enabled the options to check and send mail as my secondary accounts within my primary account.  However, I opened one of my secondary accounts, set the same theme (tree, if that makes a difference), added my other two Gmail accounts to both "check email" and "send mail as".  Yet when I hit "Compose Mail" the BlankCanvas app still pops up, whereas it still doesn't in my primary Gmail account.

Is there anything else Gmail-account-specific that could be causing it to work in some accounts but not others?

check and see if it's the same version of Gmail on all three accounts (see announcement about reporting bugs for details about how to find this.) We just need to figure out what the difference is.