Maybe your just sliding your finger down to touch the space bar?
I had the same problem. And i realized that i wasn't lifting my finger and I was sliding it.
I think what is happening is you are not completely lifting your finger off of the keypad. When you go for the space bar you are essentially swiping the keyboard down causing it to disappear. Just my thoughts.
Posted from my CrackBerry at wapforums.crackberry.com
another thing to note is that sometimes when you click on a letter it MAY not be registered ( no blue light) so when you click down on the screen, the phone will jump back to the message itself (thus removing the keyboard), thinking that you're finished with the typing.
I noticed this since moving to .83 and now .85 because I think RIM might have changed how accurate the keyboard is in detecting the location of your fingers. This makes sense because it does help in giving the user more accurate inputting of letters but unfortunately like you and I have noticed, it will disable the keyboard if you click down on the screen without a blue light showing up (indicating a letter is selected).
another thing to note is that sometimes when you click on a letter it MAY not be registered ( no blue light) so when you click down on the screen, the phone will jump back to the message itself (thus removing the keyboard), thinking that you're finished with the typing.
I noticed this since moving to .83 and now .85 because I think RIM might have changed how accurate the keyboard is in detecting the location of your fingers. This makes sense because it does help in giving the user more accurate inputting of letters but unfortunately like you and I have noticed, it will disable the keyboard if you click down on the screen without a blue light showing up (indicating a letter is selected).