This feature is unique to TreePad Business Edition and TreePad SAFE (version 7.5 or higher)
Some articles you might want to protect against accidental editing or deletion. E.g. if you have an article containing passwords and other critical information, you can set it to 'readonly'. This will prevent you from altering even the slightest detail by accidentally pressing a wrong key on your keyboard or by doing something unplanned with your mouse. Regarding tree operations, you will also not be able to delete the node containing this article, nor any subtree which contains this node⁄article, unless you first unprotect (change to 'writable') it first.
If an article is readonly you cannot immediately edit it nor delete it, unless you change it back to 'writable' first.
The fastest way to set a single article to readonly is by using the dedicated 'readonly' button in the article edit toolbar. The 'readonly' button contains a small lock icon, which displays in red colors when the current article is readonly:
The lock icon displays in grey⁄black colors when the current article can be edited:
To protect an article, first click the 'readonly' icon in the article edit toolbar, then select the menu item 'Article is readonly' (see also the screenshots above). To unprotect an article, click the 'readonly'icon, and select the menu item 'Article can be changed'.
As also mentioned above, you cannot immediately delete a subtree if it contains one or more readonly articles. You need to convert these articles to 'writable' first. For this you do not need to visit each article separately, since the Node properties dialog contains tools to change the 'readonly' state of all articles in a subtree.
More ways of setting an article to readonly or writable
(1) You can also change the 'readonly' state of the currently active article by using the 'General' page in the Node properties dialog
(2) The Node properties dialog also contains a page 'Readonly articles' which contains tools to change all articles in the current subtree to writable.