Why we can’t separately specify the scale value for X, Y and Z axis when inserting some blocks?

When inserting blocks, we can check the Uniform Scale box or uncheck it to separately specify the scale value for X, Y and Z axis,

but sometimes, the Uniform Scale is unavailable, as shown in the following picture,

When we move our cursor over the block to be inserted, we can see that there is a mark, as shown in the following picture,

This mark means that the block is annotative and applies uniform scale instead of separate value for X, Y and Z axis.

How to make blocks annotative?

When defining blocks, just check the Annotative box, at the same time, the Scale uniformly box will be checked and can’t be modified, as shown in the following picture,

Then we don’t have to set the scale for the block, we can add add scale that matches the viewport to the Object Scale List, as shown in the Annotated Object Scale dialog box, which pops up when we enter OBJECTSCALE,

How to disable Annotative of block?

Press CTRL + 1 to open the Properties Panel, then select the block to be edited, change the Yes of “Annotative” property to “No”, as shown in the following picture,