Select Only My Objects - If enabled, objects owned by other residents will not be selectable either by right clicking (or click-dragging in edit mode--deprecated).
Select Only Movable Objects - When enabled, objects that are "locked" (via the edit window in the options tab) will not be selectable.
Select Inclusive - This is used by the "click-drag highlighting box" which is the drag box shown when the object edit window is open and the mouse is left-click-dragged. If enabled, the box will only select objects if their root prim is near or inside its bounds. If disabled, an object will be selected if any part of its link set is near the box's bounds.
Show Hidden Selection - When something is selected (like a linked object with multiple prims) and this option is enabled, the outline of all objects in that link set will be shown, giving the object a wireframe-type look. When the same object is selected with this option disabled, only the edges of objects in that link set visible to the camera will be shown.
Show Light Radius For Selection - When selecting an object that has the lightfeature enabled (in the object Edit Window's "Features" tab), the radius of the light will be shown by a transparentsphere. Adjusting the "Radius" or "Intensity" options from the Edit window for that object will alter the appearance and size of the sphere.
Snap to Grid (G) - In object editing mode toggles on/off the grid and has the same effect as "Use Grid" in the edit window.
Snap Object XY to Grid (Shift-X) - Snaps the selected object to the nearest X and Y points on the grid.
Use Selection for Grid (Shift-G) - Turns on reference ruler mode in the edit window with the selected object as the 0 point for the reference grid (i.e. after selecting one prim and enabling this option), whenever the ruler mode is set to "Reference" in the object editing window, and view the grid, the 0 point will be the location of the selected prim and enabled this option on. Also, any other prims selected with reference mode for the ruler selected will also have the 0 point of their grid be the prim that was set using this option. This applies to all things that use a ruler in edit mode, position, rotation, and size.
Grid Options... (Ctrl-Shift-B) - Opens the Grid Options window from which the grid units (in meters) can be edited, grid extents (meters), enable sub-unit snapping, and adjust grid opacity; applies to all grids, position, rotation, and size.
Link (Ctrl-L) - If you have two prims or objects selected (using Shift+Left-Click or Left-Click drag) you can "link" them together into a "set". Once linked the prims can be positioned/rotated/sized together as a cohesive object. The last object clicked or the first object highlighted (if using the highlight selection box) will be set as the "root" or "parent" of the link-set, this can sometimes be important as some features use the position/rotation of the parent prim for reference. All other prims in a link-set are usually referred to as "children".
Unlink (Ctrl-Shift-L) - This will unlink a linked set of prims if you have a link-set selected. If you unlink then relink (by using Ctrl-L or Link again) without deselecting the link-set, the link order and parent will be maintained, deselecting the set will lose order and root. Also note that unlinking an object while it is physical will cause the prim pieces to explode when you deselect the set.
Focus on Selection (H) - Will adjust your camera so it is focused on the center of the object you have selected.
Zoom to Selection (Shift-H) - Will focus as well as zoom in on the selected object. Zoom auto-adjusts to a default zoom distance based on the size of the object.
Take Object - The object will be taken out of world and placed inside the object folder in your inventory.
Take Copy - A copy of the object will be taken to your inventory and a copy of the object will remain in-world.
Save Object Back to My Inventory - When you drag an object out of your inventory and then make changes to it, you can select this option and it will replace the object in your inventory with the one you have made changes to (and leave the object in-world). Note that it does not update any name or description changes you have made to the object.
Save Object Back to Object Contents - When you drag an object out of another object's contents, then make changes to that object, selecting this option will update the object in the other object's contents while leaving the object in-world. Note that this does not work if you change the name of the object while it is in-world and also that description changes do not save.
Show Script Warning/Error Window - Shows the script warning/error window to which some script errors are sent (if you have "Show script warnings and errors as regular chat" disabled in Preferences > Chat).
Recompile Scripts in Selection - All scripts in the selected object will be recompiled, a window will pop up showing the progress, closing the window cancels the task and prints an error.
Reset Scripts in Selection - Resets the scripts in the selected object, a window will pop up with the progress, closing this window cancels the task of resetting and prints an error.
Set Scripts to Running in Selection - Will set the scripts in the selected object to their running state (the same as checking the Running checkbox). Has no effect if the scripts are already running.
Set Scripts to Not Running in Selection - All running scripts in selected object will be set to "Not Running" (same effect as unchecking the Running checkbox in script editor window). Has no effect on scripts already set to "Not Running".